diff --git a/src-self-hosted/clang.zig b/src-self-hosted/clang.zig
index e2608e6537..db76185ab9 100644
--- a/src-self-hosted/clang.zig
+++ b/src-self-hosted/clang.zig
@@ -1,3 +1,5 @@
+const builtin = @import("builtin");
+
 pub const struct_ZigClangAPSInt = @OpaqueType();
 pub const struct_ZigClangAPFloat = @OpaqueType();
 pub const struct_ZigClangASTContext = @OpaqueType();
@@ -938,7 +940,7 @@ pub const struct_ZigClangExprEvalResult = extern struct {
 
 pub const struct_ZigClangAPValue = extern struct {
     Kind: ZigClangAPValue_ValueKind,
-    Data: [68]u8, // TODO: is there a way to statically assert that this matches the .h?
+    Data: if (builtin.os == .windows) [52]u8 else [68]u8,
 };
 
 pub const ZigClangAPValue_ValueKind = extern enum {
diff --git a/src/zig_clang.h b/src/zig_clang.h
index ffa2291d9a..183aaef681 100644
--- a/src/zig_clang.h
+++ b/src/zig_clang.h
@@ -47,7 +47,12 @@ enum ZigClangAPValue_ValueKind {
 
 struct ZigClangAPValue {
     enum ZigClangAPValue_ValueKind Kind;
-    char Data[68]; // experimentally-derived size of clang::APValue::DataType
+    // experimentally-derived size of clang::APValue::DataType
+#ifdef _WIN32
+    char Data[52];
+#else
+    char Data[68];
+#endif
 };
 
 struct ZigClangExprEvalResult {