diff --git a/kotlinpoet/src/jvmMain/kotlin/com/squareup/kotlinpoet/TypeSpec.kt b/kotlinpoet/src/jvmMain/kotlin/com/squareup/kotlinpoet/TypeSpec.kt
index b1dc36123..6f506e870 100644
--- a/kotlinpoet/src/jvmMain/kotlin/com/squareup/kotlinpoet/TypeSpec.kt
+++ b/kotlinpoet/src/jvmMain/kotlin/com/squareup/kotlinpoet/TypeSpec.kt
@@ -159,7 +159,7 @@ public class TypeSpec private constructor(
         }
 
         if (allSuperTypes.isNotEmpty()) {
-          codeWriter.emitCode(allSuperTypes.joinToCode(separator = ", ", prefix = " : "))
+          codeWriter.emitCode(allSuperTypes.joinToCode(prefix = " : "))
         }
         if (hasNoBody) {
           codeWriter.emit(" {\n}")