diff --git a/fabric-object-builder-api-v1/src/main/java/net/fabricmc/fabric/api/object/builder/v1/block/entity/FabricBlockEntityTypeBuilder.java b/fabric-object-builder-api-v1/src/main/java/net/fabricmc/fabric/api/object/builder/v1/block/entity/FabricBlockEntityTypeBuilder.java
index dc62f9512..87e9df904 100644
--- a/fabric-object-builder-api-v1/src/main/java/net/fabricmc/fabric/api/object/builder/v1/block/entity/FabricBlockEntityTypeBuilder.java
+++ b/fabric-object-builder-api-v1/src/main/java/net/fabricmc/fabric/api/object/builder/v1/block/entity/FabricBlockEntityTypeBuilder.java
@@ -16,6 +16,10 @@
 
 package net.fabricmc.fabric.api.object.builder.v1.block.entity;
 
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
 import com.mojang.datafixers.types.Type;
 
 import net.minecraft.block.Block;
@@ -31,15 +35,40 @@ import net.minecraft.util.math.BlockPos;
  */
 public final class FabricBlockEntityTypeBuilder<T extends BlockEntity> {
 	private final Factory<? extends T> factory;
-	private final Block[] blocks;
+	private final List<Block> blocks;
 
-	private FabricBlockEntityTypeBuilder(Factory<? extends T> factory, Block[] blocks) {
+	private FabricBlockEntityTypeBuilder(Factory<? extends T> factory, List<Block> blocks) {
 		this.factory = factory;
 		this.blocks = blocks;
 	}
 
 	public static <T extends BlockEntity> FabricBlockEntityTypeBuilder<T> create(Factory<? extends T> factory, Block... blocks) {
-		return new FabricBlockEntityTypeBuilder<>(factory, blocks);
+		List<Block> blocksList = new ArrayList<>(blocks.length);
+		Collections.addAll(blocksList, blocks);
+
+		return new FabricBlockEntityTypeBuilder<>(factory, blocksList);
+	}
+
+	/**
+	 * Adds a supported block for the block entity type.
+	 *
+	 * @param block the supported block
+	 * @return this builder
+	 */
+	public FabricBlockEntityTypeBuilder<T> addBlock(Block block) {
+		this.blocks.add(block);
+		return this;
+	}
+
+	/**
+	 * Adds supported blocks for the block entity type.
+	 *
+	 * @param blocks the supported blocks
+	 * @return this builder
+	 */
+	public FabricBlockEntityTypeBuilder<T> addBlocks(Block... blocks) {
+		Collections.addAll(this.blocks, blocks);
+		return this;
 	}
 
 	public BlockEntityType<T> build() {
@@ -47,7 +76,7 @@ public final class FabricBlockEntityTypeBuilder<T extends BlockEntity> {
 	}
 
 	public BlockEntityType<T> build(Type<?> type) {
-		return BlockEntityType.Builder.<T>create(factory::create, blocks)
+		return BlockEntityType.Builder.<T>create(factory::create, blocks.toArray(new Block[0]))
 				.build(type);
 	}
 
diff --git a/fabric-object-builder-api-v1/src/testmod/java/net/fabricmc/fabric/test/object/builder/BlockEntityTypeBuilderTest.java b/fabric-object-builder-api-v1/src/testmod/java/net/fabricmc/fabric/test/object/builder/BlockEntityTypeBuilderTest.java
new file mode 100644
index 000000000..352b2a08f
--- /dev/null
+++ b/fabric-object-builder-api-v1/src/testmod/java/net/fabricmc/fabric/test/object/builder/BlockEntityTypeBuilderTest.java
@@ -0,0 +1,117 @@
+/*
+ * Copyright (c) 2016, 2017, 2018, 2019 FabricMC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.fabricmc.fabric.test.object.builder;
+
+import net.minecraft.block.AbstractBlock;
+import net.minecraft.block.Block;
+import net.minecraft.block.BlockEntityProvider;
+import net.minecraft.block.BlockState;
+import net.minecraft.block.Blocks;
+import net.minecraft.block.MapColor;
+import net.minecraft.block.entity.BlockEntity;
+import net.minecraft.block.entity.BlockEntityType;
+import net.minecraft.entity.player.PlayerEntity;
+import net.minecraft.item.BlockItem;
+import net.minecraft.item.Item;
+import net.minecraft.item.ItemGroup;
+import net.minecraft.text.Text;
+import net.minecraft.text.TranslatableText;
+import net.minecraft.util.ActionResult;
+import net.minecraft.util.Hand;
+import net.minecraft.util.Identifier;
+import net.minecraft.util.hit.BlockHitResult;
+import net.minecraft.util.math.BlockPos;
+import net.minecraft.util.registry.Registry;
+import net.minecraft.world.World;
+
+import net.fabricmc.api.ModInitializer;
+import net.fabricmc.fabric.api.object.builder.v1.block.entity.FabricBlockEntityTypeBuilder;
+
+public class BlockEntityTypeBuilderTest implements ModInitializer {
+	private static final Identifier INITIAL_BETRAYAL_BLOCK_ID = ObjectBuilderTestConstants.id("initial_betrayal_block");
+	private static final Block INITIAL_BETRAYAL_BLOCK = new BetrayalBlock(MapColor.BLUE);
+
+	private static final Identifier ADDED_BETRAYAL_BLOCK_ID = ObjectBuilderTestConstants.id("added_betrayal_block");
+	private static final Block ADDED_BETRAYAL_BLOCK = new BetrayalBlock(MapColor.GREEN);
+
+	private static final Identifier FIRST_MULTI_BETRAYAL_BLOCK_ID = ObjectBuilderTestConstants.id("first_multi_betrayal_block");
+	private static final Block FIRST_MULTI_BETRAYAL_BLOCK = new BetrayalBlock(MapColor.RED);
+
+	private static final Identifier SECOND_MULTI_BETRAYAL_BLOCK_ID = ObjectBuilderTestConstants.id("second_multi_betrayal_block");
+	private static final Block SECOND_MULTI_BETRAYAL_BLOCK = new BetrayalBlock(MapColor.YELLOW);
+
+	private static final Identifier BLOCK_ENTITY_TYPE_ID = ObjectBuilderTestConstants.id("betrayal_block");
+	public static final BlockEntityType<?> BLOCK_ENTITY_TYPE = FabricBlockEntityTypeBuilder.create(BetrayalBlockEntity::new, INITIAL_BETRAYAL_BLOCK)
+			.addBlock(ADDED_BETRAYAL_BLOCK)
+			.addBlocks(FIRST_MULTI_BETRAYAL_BLOCK, SECOND_MULTI_BETRAYAL_BLOCK)
+			.build();
+
+	@Override
+	public void onInitialize() {
+		register(INITIAL_BETRAYAL_BLOCK_ID, INITIAL_BETRAYAL_BLOCK);
+		register(ADDED_BETRAYAL_BLOCK_ID, ADDED_BETRAYAL_BLOCK);
+		register(FIRST_MULTI_BETRAYAL_BLOCK_ID, FIRST_MULTI_BETRAYAL_BLOCK);
+		register(SECOND_MULTI_BETRAYAL_BLOCK_ID, SECOND_MULTI_BETRAYAL_BLOCK);
+
+		Registry.register(Registry.BLOCK_ENTITY_TYPE, BLOCK_ENTITY_TYPE_ID, BLOCK_ENTITY_TYPE);
+	}
+
+	private static void register(Identifier id, Block block) {
+		Registry.register(Registry.BLOCK, id, block);
+
+		Item item = new BlockItem(block, new Item.Settings().group(ItemGroup.MISC));
+		Registry.register(Registry.ITEM, id, item);
+	}
+
+	private static class BetrayalBlock extends Block implements BlockEntityProvider {
+		private BetrayalBlock(MapColor color) {
+			super(AbstractBlock.Settings.copy(Blocks.STONE).mapColor(color));
+		}
+
+		@Override
+		public ActionResult onUse(BlockState state, World world, BlockPos pos, PlayerEntity player, Hand hand, BlockHitResult hit) {
+			if (!world.isClient()) {
+				BlockEntity blockEntity = world.getBlockEntity(pos);
+
+				if (blockEntity == null) {
+					throw new AssertionError("Missing block entity for betrayal block at " + pos);
+				} else if (!BLOCK_ENTITY_TYPE.equals(blockEntity.getType())) {
+					Identifier id = BlockEntityType.getId(blockEntity.getType());
+					throw new AssertionError("Incorrect block entity for betrayal block at " + pos + ": " + id);
+				}
+
+				Text posText = new TranslatableText("chat.coordinates", pos.getX(), pos.getY(), pos.getZ());
+				Text message = new TranslatableText("text.fabric-object-builder-api-v1-testmod.block_entity_type_success", posText, BLOCK_ENTITY_TYPE_ID);
+
+				player.sendMessage(message, false);
+			}
+
+			return ActionResult.SUCCESS;
+		}
+
+		@Override
+		public BlockEntity createBlockEntity(BlockPos pos, BlockState state) {
+			return new BetrayalBlockEntity(pos, state);
+		}
+	}
+
+	private static class BetrayalBlockEntity extends BlockEntity {
+		private BetrayalBlockEntity(BlockPos pos, BlockState state) {
+			super(BLOCK_ENTITY_TYPE, pos, state);
+		}
+	}
+}
diff --git a/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/blockstates/added_betrayal_block.json b/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/blockstates/added_betrayal_block.json
new file mode 100644
index 000000000..24490093a
--- /dev/null
+++ b/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/blockstates/added_betrayal_block.json
@@ -0,0 +1,7 @@
+{
+  "variants": {
+    "": {
+      "model": "fabric-object-builder-api-v1-testmod:block/added_betrayal_block"
+    }
+  }
+}
diff --git a/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/blockstates/first_multi_betrayal_block.json b/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/blockstates/first_multi_betrayal_block.json
new file mode 100644
index 000000000..10eb5394d
--- /dev/null
+++ b/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/blockstates/first_multi_betrayal_block.json
@@ -0,0 +1,7 @@
+{
+  "variants": {
+    "": {
+      "model": "fabric-object-builder-api-v1-testmod:block/first_multi_betrayal_block"
+    }
+  }
+}
diff --git a/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/blockstates/initial_betrayal_block.json b/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/blockstates/initial_betrayal_block.json
new file mode 100644
index 000000000..80ef9d66a
--- /dev/null
+++ b/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/blockstates/initial_betrayal_block.json
@@ -0,0 +1,7 @@
+{
+  "variants": {
+    "": {
+      "model": "fabric-object-builder-api-v1-testmod:block/initial_betrayal_block"
+    }
+  }
+}
diff --git a/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/blockstates/second_multi_betrayal_block.json b/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/blockstates/second_multi_betrayal_block.json
new file mode 100644
index 000000000..dfd3d177a
--- /dev/null
+++ b/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/blockstates/second_multi_betrayal_block.json
@@ -0,0 +1,7 @@
+{
+  "variants": {
+    "": {
+      "model": "fabric-object-builder-api-v1-testmod:block/second_multi_betrayal_block"
+    }
+  }
+}
diff --git a/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/lang/en_us.json b/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/lang/en_us.json
new file mode 100644
index 000000000..e2cf21775
--- /dev/null
+++ b/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/lang/en_us.json
@@ -0,0 +1,7 @@
+{
+  "block.fabric-object-builder-api-v1-testmod.added_betrayal_block": "Added Betrayal Block",
+  "block.fabric-object-builder-api-v1-testmod.first_multi_betrayal_block": "First Multi Betrayal Block",
+  "block.fabric-object-builder-api-v1-testmod.initial_betrayal_block": "Initial Betrayal Block",
+  "block.fabric-object-builder-api-v1-testmod.second_multi_betrayal_block": "Second Multi Betrayal Block",
+  "text.fabric-object-builder-api-v1-testmod.block_entity_type_success": "Betrayal block at %s has correct block entity type: %s"
+}
diff --git a/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/models/block/added_betrayal_block.json b/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/models/block/added_betrayal_block.json
new file mode 100644
index 000000000..2d8c77731
--- /dev/null
+++ b/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/models/block/added_betrayal_block.json
@@ -0,0 +1,6 @@
+{
+  "parent": "minecraft:block/cube_all",
+  "textures": {
+    "all": "fabric-object-builder-api-v1-testmod:block/added_betrayal_block"
+  }
+}
diff --git a/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/models/block/first_multi_betrayal_block.json b/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/models/block/first_multi_betrayal_block.json
new file mode 100644
index 000000000..c944798e4
--- /dev/null
+++ b/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/models/block/first_multi_betrayal_block.json
@@ -0,0 +1,6 @@
+{
+  "parent": "minecraft:block/cube_all",
+  "textures": {
+    "all": "fabric-object-builder-api-v1-testmod:block/first_multi_betrayal_block"
+  }
+}
diff --git a/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/models/block/initial_betrayal_block.json b/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/models/block/initial_betrayal_block.json
new file mode 100644
index 000000000..4dbc4adba
--- /dev/null
+++ b/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/models/block/initial_betrayal_block.json
@@ -0,0 +1,6 @@
+{
+  "parent": "minecraft:block/cube_all",
+  "textures": {
+    "all": "fabric-object-builder-api-v1-testmod:block/initial_betrayal_block"
+  }
+}
diff --git a/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/models/block/second_multi_betrayal_block.json b/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/models/block/second_multi_betrayal_block.json
new file mode 100644
index 000000000..92a475c44
--- /dev/null
+++ b/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/models/block/second_multi_betrayal_block.json
@@ -0,0 +1,6 @@
+{
+  "parent": "minecraft:block/cube_all",
+  "textures": {
+    "all": "fabric-object-builder-api-v1-testmod:block/second_multi_betrayal_block"
+  }
+}
diff --git a/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/models/item/added_betrayal_block.json b/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/models/item/added_betrayal_block.json
new file mode 100644
index 000000000..cea465dbc
--- /dev/null
+++ b/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/models/item/added_betrayal_block.json
@@ -0,0 +1,3 @@
+{
+  "parent": "fabric-object-builder-api-v1-testmod:block/added_betrayal_block"
+}
diff --git a/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/models/item/first_multi_betrayal_block.json b/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/models/item/first_multi_betrayal_block.json
new file mode 100644
index 000000000..7dd11b7da
--- /dev/null
+++ b/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/models/item/first_multi_betrayal_block.json
@@ -0,0 +1,3 @@
+{
+  "parent": "fabric-object-builder-api-v1-testmod:block/first_multi_betrayal_block"
+}
diff --git a/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/models/item/initial_betrayal_block.json b/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/models/item/initial_betrayal_block.json
new file mode 100644
index 000000000..03d9b4929
--- /dev/null
+++ b/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/models/item/initial_betrayal_block.json
@@ -0,0 +1,3 @@
+{
+  "parent": "fabric-object-builder-api-v1-testmod:block/initial_betrayal_block"
+}
diff --git a/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/models/item/second_multi_betrayal_block.json b/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/models/item/second_multi_betrayal_block.json
new file mode 100644
index 000000000..389368cec
--- /dev/null
+++ b/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/models/item/second_multi_betrayal_block.json
@@ -0,0 +1,3 @@
+{
+  "parent": "fabric-object-builder-api-v1-testmod:block/second_multi_betrayal_block"
+}
diff --git a/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/textures/block/added_betrayal_block.png b/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/textures/block/added_betrayal_block.png
new file mode 100644
index 000000000..27f6ec975
Binary files /dev/null and b/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/textures/block/added_betrayal_block.png differ
diff --git a/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/textures/block/first_multi_betrayal_block.png b/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/textures/block/first_multi_betrayal_block.png
new file mode 100644
index 000000000..0f0be0ab1
Binary files /dev/null and b/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/textures/block/first_multi_betrayal_block.png differ
diff --git a/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/textures/block/initial_betrayal_block.png b/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/textures/block/initial_betrayal_block.png
new file mode 100644
index 000000000..5cc4eae1b
Binary files /dev/null and b/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/textures/block/initial_betrayal_block.png differ
diff --git a/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/textures/block/second_multi_betrayal_block.png b/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/textures/block/second_multi_betrayal_block.png
new file mode 100644
index 000000000..8743efa3f
Binary files /dev/null and b/fabric-object-builder-api-v1/src/testmod/resources/assets/fabric-object-builder-api-v1-testmod/textures/block/second_multi_betrayal_block.png differ
diff --git a/fabric-object-builder-api-v1/src/testmod/resources/fabric.mod.json b/fabric-object-builder-api-v1/src/testmod/resources/fabric.mod.json
index cd56198f3..6aa22767c 100644
--- a/fabric-object-builder-api-v1/src/testmod/resources/fabric.mod.json
+++ b/fabric-object-builder-api-v1/src/testmod/resources/fabric.mod.json
@@ -16,11 +16,13 @@
     "FabricMC"
   ],
   "depends": {
+    "fabric-resource-loader-v0": "*",
     "fabric-object-builder-api-v1": "*"
   },
   "description": "Test mod for fabric object builder API v1.",
   "entrypoints": {
     "main": [
+      "net.fabricmc.fabric.test.object.builder.BlockEntityTypeBuilderTest",
       "net.fabricmc.fabric.test.object.builder.CriterionRegistryTest::init",
       "net.fabricmc.fabric.test.object.builder.VillagerTypeTest1",
       "net.fabricmc.fabric.test.object.builder.VillagerTypeTest2"