diff --git a/modules/kobalt-plugin-api/src/main/kotlin/com/beust/kobalt/internal/JvmCompilerPlugin.kt b/modules/kobalt-plugin-api/src/main/kotlin/com/beust/kobalt/internal/JvmCompilerPlugin.kt
index 51f10052..fd473f8b 100644
--- a/modules/kobalt-plugin-api/src/main/kotlin/com/beust/kobalt/internal/JvmCompilerPlugin.kt
+++ b/modules/kobalt-plugin-api/src/main/kotlin/com/beust/kobalt/internal/JvmCompilerPlugin.kt
@@ -187,8 +187,8 @@ open class JvmCompilerPlugin @Inject constructor(
             var done = false
             // The directory where the classes get compiled
             val buildDirectory =
-                    if (isTest) File(project.buildDirectory, KFiles.TEST_CLASSES_DIR)
-                    else File(project.classesDir(context))
+                    if (isTest) File(KFiles.joinDir(project.directory, project.buildDirectory, KFiles.TEST_CLASSES_DIR))
+                    else File(KFiles.joinDir(project.directory, project.classesDir(context)))
 
             allCompilersSorted.doWhile({ ! done }) { compiler ->
                 val compilerResults = compilerUtils.invokeCompiler(project, context, compiler,