diff --git a/fixtures-processor/src/main/kotlin/com/theblueground/fixtures/ProcessedParameterMapper.kt b/fixtures-processor/src/main/kotlin/com/theblueground/fixtures/ProcessedParameterMapper.kt
index 54c9439..12cf410 100644
--- a/fixtures-processor/src/main/kotlin/com/theblueground/fixtures/ProcessedParameterMapper.kt
+++ b/fixtures-processor/src/main/kotlin/com/theblueground/fixtures/ProcessedParameterMapper.kt
@@ -3,6 +3,7 @@ package com.theblueground.fixtures
 import com.google.devtools.ksp.symbol.KSClassDeclaration
 import com.google.devtools.ksp.symbol.KSDeclaration
 import com.google.devtools.ksp.symbol.KSType
+import com.google.devtools.ksp.symbol.KSTypeAlias
 import com.google.devtools.ksp.symbol.KSValueParameter
 import com.squareup.kotlinpoet.ParameterizedTypeName.Companion.parameterizedBy
 import com.squareup.kotlinpoet.TypeName
@@ -20,19 +21,18 @@ internal class ProcessedParameterMapper(
 
     fun mapParameter(parameterValue: KSValueParameter): ProcessedFixtureParameter {
         val resolvedType = parameterValue.type.resolve()
-        return mapParameter(
-            parameterValue = parameterValue,
-            parameterType = resolvedType,
-            parameterClassDeclaration = (resolvedType.declaration as KSClassDeclaration),
-        )
+        return when (val declaration = resolvedType.declaration) {
+            is KSTypeAlias -> mapParameter(parameterValue, declaration.type.resolve())
+            else -> mapParameter(parameterValue, resolvedType)
+        }
     }
 
     private fun mapParameter(
         parameterValue: KSValueParameter,
         parameterType: KSType,
-        parameterClassDeclaration: KSClassDeclaration,
     ): ProcessedFixtureParameter {
         val name = parameterValue.name!!.asString()
+        val parameterClassDeclaration = parameterType.declaration as KSClassDeclaration
 
         return when {
             parameterType.hasFixtureAdapter(processedFixtureAdapters) -> mapFixtureAdapterParameter(
diff --git a/fixtures-processor/src/test/kotlin/com/theblueground/fixtures/FixtureProcessorTest.kt b/fixtures-processor/src/test/kotlin/com/theblueground/fixtures/FixtureProcessorTest.kt
index a3410e7..d342b84 100644
--- a/fixtures-processor/src/test/kotlin/com/theblueground/fixtures/FixtureProcessorTest.kt
+++ b/fixtures-processor/src/test/kotlin/com/theblueground/fixtures/FixtureProcessorTest.kt
@@ -271,6 +271,51 @@ class FixtureProcessorTest : KSPTest() {
         assertThat(secondTimeGeneratedContent).doesNotMatch(firstTimeGeneratedContent)
     }
 
+    @Test
+    fun `should generate a builder function with resolved type for typealias`() {
+        // Given
+        val fixtureSource = """
+                    package $packageName
+
+                    import com.theblueground.fixtures.Fixture
+
+                    import java.math.BigDecimal
+
+                    @Fixture
+                    data class $fixtureName(
+                        val bigDecimalAliasValue: BigDecimalAlias,
+                    )
+
+                    typealias BigDecimalAlias = BigDecimal
+        """.trimIndent()
+        val fixtureFile = kotlin(name = "$fixtureName.kt", contents = fixtureSource)
+
+        // When
+        val result = compile(
+            arguments = mapOf("fixtures.run" to "true"),
+            sourceFiles = listOf(fixtureFile),
+        )
+        val generatedContent = getGeneratedContent(
+            packageName = packageName,
+            filename = "${fixtureName}Fixture.kt",
+        )
+
+        // Then
+        assertThat(result.exitCode).isEqualTo(KotlinCompilation.ExitCode.OK)
+        val expected = """
+            package $packageName
+
+            import java.math.BigDecimal
+
+            public fun create$fixtureName(bigDecimalAliasValue: BigDecimal = BigDecimal.ZERO): TestClass =
+                $packageName.$fixtureName(
+            	bigDecimalAliasValue = bigDecimalAliasValue
+            )
+
+        """.trimIndent()
+        assertThat(generatedContent).isEqualTo(expected)
+    }
+
     @Test
     fun `should not generate a builder function while not running tests`() {
         // Given