diff --git a/executor/invoker/src/commonMain/kotlin/io/github/charlietap/chasm/executor/invoker/dispatch/referencefused/RefTestDispatcher.kt b/executor/invoker/src/commonMain/kotlin/io/github/charlietap/chasm/executor/invoker/dispatch/referencefused/RefTestDispatcher.kt
new file mode 100644
index 00000000..e631b12d
--- /dev/null
+++ b/executor/invoker/src/commonMain/kotlin/io/github/charlietap/chasm/executor/invoker/dispatch/referencefused/RefTestDispatcher.kt
@@ -0,0 +1,20 @@
+package io.github.charlietap.chasm.executor.invoker.dispatch.referencefused
+
+import io.github.charlietap.chasm.executor.invoker.instruction.referencefused.RefTestExecutor
+import io.github.charlietap.chasm.executor.runtime.dispatch.DispatchableInstruction
+import io.github.charlietap.chasm.executor.runtime.execution.Executor
+import io.github.charlietap.chasm.executor.runtime.instruction.FusedReferenceInstruction
+
+fun RefTestDispatcher(
+    instruction: FusedReferenceInstruction.RefTest,
+) = RefTestDispatcher(
+    instruction = instruction,
+    executor = ::RefTestExecutor,
+)
+
+internal inline fun RefTestDispatcher(
+    instruction: FusedReferenceInstruction.RefTest,
+    crossinline executor: Executor<FusedReferenceInstruction.RefTest>,
+): DispatchableInstruction = { context ->
+    executor(context, instruction)
+}
diff --git a/executor/invoker/src/commonMain/kotlin/io/github/charlietap/chasm/executor/invoker/instruction/referencefused/RefTestExecutor.kt b/executor/invoker/src/commonMain/kotlin/io/github/charlietap/chasm/executor/invoker/instruction/referencefused/RefTestExecutor.kt
new file mode 100644
index 00000000..232128af
--- /dev/null
+++ b/executor/invoker/src/commonMain/kotlin/io/github/charlietap/chasm/executor/invoker/instruction/referencefused/RefTestExecutor.kt
@@ -0,0 +1,38 @@
+package io.github.charlietap.chasm.executor.invoker.instruction.referencefused
+
+import io.github.charlietap.chasm.executor.invoker.type.TypeOf
+import io.github.charlietap.chasm.executor.invoker.type.TypeOfReferenceValue
+import io.github.charlietap.chasm.executor.runtime.execution.ExecutionContext
+import io.github.charlietap.chasm.executor.runtime.instruction.FusedReferenceInstruction
+import io.github.charlietap.chasm.type.ReferenceType
+import io.github.charlietap.chasm.type.matching.ReferenceTypeMatcher
+import io.github.charlietap.chasm.type.matching.TypeMatcher
+
+internal fun RefTestExecutor(
+    context: ExecutionContext,
+    instruction: FusedReferenceInstruction.RefTest,
+) = RefTestExecutor(
+    context = context,
+    instruction = instruction,
+    referenceTypeMatcher = ::ReferenceTypeMatcher,
+    typeOfReferenceValue = ::TypeOfReferenceValue,
+)
+
+internal inline fun RefTestExecutor(
+    context: ExecutionContext,
+    instruction: FusedReferenceInstruction.RefTest,
+    crossinline referenceTypeMatcher: TypeMatcher<ReferenceType>,
+    crossinline typeOfReferenceValue: TypeOf<Long, ReferenceType>,
+) {
+    val stack = context.vstack
+    val store = context.store
+    val frame = context.cstack.peekFrame()
+    val moduleInstance = frame.instance
+
+    val referenceType = typeOfReferenceValue(instruction.reference(stack), store, moduleInstance)
+    if (referenceTypeMatcher(referenceType, instruction.referenceType, context)) {
+        instruction.destination(1L, stack)
+    } else {
+        instruction.destination(0L, stack)
+    }
+}
diff --git a/executor/runtime-internal/src/commonMain/kotlin/io/github/charlietap/chasm/executor/runtime/instruction/FusedReferenceInstruction.kt b/executor/runtime-internal/src/commonMain/kotlin/io/github/charlietap/chasm/executor/runtime/instruction/FusedReferenceInstruction.kt
index 72f08020..89f3b8e9 100644
--- a/executor/runtime-internal/src/commonMain/kotlin/io/github/charlietap/chasm/executor/runtime/instruction/FusedReferenceInstruction.kt
+++ b/executor/runtime-internal/src/commonMain/kotlin/io/github/charlietap/chasm/executor/runtime/instruction/FusedReferenceInstruction.kt
@@ -1,5 +1,7 @@
 package io.github.charlietap.chasm.executor.runtime.instruction
 
+import io.github.charlietap.chasm.type.ReferenceType
+
 sealed interface FusedReferenceInstruction : LinkedInstruction {
 
     data class RefEq(
@@ -17,4 +19,10 @@ sealed interface FusedReferenceInstruction : LinkedInstruction {
         val destination: StoreOp,
         val reference: Long,
     ) : FusedReferenceInstruction
+
+    data class RefTest(
+        val reference: LoadOp,
+        val destination: StoreOp,
+        val referenceType: ReferenceType,
+    ) : FusedReferenceInstruction
 }
diff --git a/ir/src/commonMain/kotlin/io/github/charlietap/chasm/ir/instruction/FusedReferenceInstruction.kt b/ir/src/commonMain/kotlin/io/github/charlietap/chasm/ir/instruction/FusedReferenceInstruction.kt
index 3fe53460..90896557 100644
--- a/ir/src/commonMain/kotlin/io/github/charlietap/chasm/ir/instruction/FusedReferenceInstruction.kt
+++ b/ir/src/commonMain/kotlin/io/github/charlietap/chasm/ir/instruction/FusedReferenceInstruction.kt
@@ -1,6 +1,7 @@
 package io.github.charlietap.chasm.ir.instruction
 
 import io.github.charlietap.chasm.type.HeapType
+import io.github.charlietap.chasm.type.ReferenceType
 
 sealed interface FusedReferenceInstruction : Instruction {
 
@@ -19,4 +20,10 @@ sealed interface FusedReferenceInstruction : Instruction {
         val destination: FusedDestination,
         val type: HeapType,
     ) : FusedReferenceInstruction
+
+    data class RefTest(
+        val reference: FusedOperand,
+        val destination: FusedDestination,
+        val referenceType: ReferenceType,
+    ) : FusedReferenceInstruction
 }
diff --git a/optimiser/src/commonMain/kotlin/io/github/charlietap/chasm/optimiser/passes/fusion/ReferenceInstructionFuser.kt b/optimiser/src/commonMain/kotlin/io/github/charlietap/chasm/optimiser/passes/fusion/ReferenceInstructionFuser.kt
index 1360ce09..2845154e 100644
--- a/optimiser/src/commonMain/kotlin/io/github/charlietap/chasm/optimiser/passes/fusion/ReferenceInstructionFuser.kt
+++ b/optimiser/src/commonMain/kotlin/io/github/charlietap/chasm/optimiser/passes/fusion/ReferenceInstructionFuser.kt
@@ -131,6 +131,40 @@ internal inline fun ReferenceInstructionFuser(
 
         nextIndex
     }
+    is ReferenceInstruction.RefTest -> {
+        var nextIndex = index
+
+        val reference = input.getOrNull(index - 1)?.let(operandFactory)
+        val destination = input.getOrNull(index + 1).let(destinationFactory)
+
+        val instruction = if (reference == null && destination == FusedDestination.ValueStack) {
+            instruction
+        } else {
+            when {
+                reference == null -> FusedReferenceInstruction.RefTest(
+                    reference = FusedOperand.ValueStack,
+                    destination = destination,
+                    referenceType = instruction.referenceType,
+                )
+                else -> {
+                    output.removeLast()
+                    FusedReferenceInstruction.RefTest(
+                        reference = reference,
+                        destination = destination,
+                        referenceType = instruction.referenceType,
+                    )
+                }
+            }
+        }
+
+        output.add(instruction)
+
+        if (destination != FusedDestination.ValueStack) {
+            nextIndex++
+        }
+
+        nextIndex
+    }
     else -> {
         output.add(instruction)
         index
diff --git a/predecoder/src/commonMain/kotlin/io/github/charlietap/chasm/predecoder/instruction/referencefused/FusedReferenceInstructionPredecoder.kt b/predecoder/src/commonMain/kotlin/io/github/charlietap/chasm/predecoder/instruction/referencefused/FusedReferenceInstructionPredecoder.kt
index 8b6e70fb..ddbac522 100644
--- a/predecoder/src/commonMain/kotlin/io/github/charlietap/chasm/predecoder/instruction/referencefused/FusedReferenceInstructionPredecoder.kt
+++ b/predecoder/src/commonMain/kotlin/io/github/charlietap/chasm/predecoder/instruction/referencefused/FusedReferenceInstructionPredecoder.kt
@@ -6,12 +6,14 @@ import io.github.charlietap.chasm.executor.invoker.dispatch.Dispatcher
 import io.github.charlietap.chasm.executor.invoker.dispatch.referencefused.RefEqDispatcher
 import io.github.charlietap.chasm.executor.invoker.dispatch.referencefused.RefIsNullDispatcher
 import io.github.charlietap.chasm.executor.invoker.dispatch.referencefused.RefNullDispatcher
+import io.github.charlietap.chasm.executor.invoker.dispatch.referencefused.RefTestDispatcher
 import io.github.charlietap.chasm.executor.runtime.dispatch.DispatchableInstruction
 import io.github.charlietap.chasm.executor.runtime.error.ModuleTrapError
 import io.github.charlietap.chasm.executor.runtime.ext.toLong
 import io.github.charlietap.chasm.executor.runtime.instruction.FusedReferenceInstruction.RefEq
 import io.github.charlietap.chasm.executor.runtime.instruction.FusedReferenceInstruction.RefIsNull
 import io.github.charlietap.chasm.executor.runtime.instruction.FusedReferenceInstruction.RefNull
+import io.github.charlietap.chasm.executor.runtime.instruction.FusedReferenceInstruction.RefTest
 import io.github.charlietap.chasm.executor.runtime.value.ReferenceValue
 import io.github.charlietap.chasm.ir.instruction.FusedReferenceInstruction
 import io.github.charlietap.chasm.predecoder.LoadFactory
@@ -30,6 +32,7 @@ internal fun FusedReferenceInstructionPredecoder(
         refEqDispatcher = ::RefEqDispatcher,
         refIsNullDispatcher = ::RefIsNullDispatcher,
         refNullDispatcher = ::RefNullDispatcher,
+        refTestDispatcher = ::RefTestDispatcher,
     )
 
 internal inline fun FusedReferenceInstructionPredecoder(
@@ -40,6 +43,7 @@ internal inline fun FusedReferenceInstructionPredecoder(
     crossinline refEqDispatcher: Dispatcher<RefEq>,
     crossinline refIsNullDispatcher: Dispatcher<RefIsNull>,
     crossinline refNullDispatcher: Dispatcher<RefNull>,
+    crossinline refTestDispatcher: Dispatcher<RefTest>,
 ): Result<DispatchableInstruction, ModuleTrapError> = binding {
     when (instruction) {
         is FusedReferenceInstruction.RefEq -> {
@@ -72,5 +76,17 @@ internal inline fun FusedReferenceInstructionPredecoder(
             val reference = ReferenceValue.Null(instruction.type).toLong()
             refNullDispatcher(RefNull(destination, reference))
         }
+        is FusedReferenceInstruction.RefTest -> {
+            val reference = loadFactory(context, instruction.reference)
+            val destination = storeFactory(context, instruction.destination)
+
+            refTestDispatcher(
+                RefTest(
+                    reference = reference,
+                    destination = destination,
+                    referenceType = instruction.referenceType,
+                ),
+            )
+        }
     }
 }