diff --git a/tools/gen_shims/main.go b/tools/gen_shims/main.go
index 2ce59a0c..38fc4cc1 100644
--- a/tools/gen_shims/main.go
+++ b/tools/gen_shims/main.go
@@ -3,7 +3,6 @@ package main
 import (
 	"bytes"
 	"fmt"
-	"github.com/go-json-experiment/json"
 	"go/types"
 	"log"
 	"maps"
@@ -12,6 +11,8 @@ import (
 	"slices"
 	"strings"
 
+	"github.com/go-json-experiment/json"
+
 	"golang.org/x/text/cases"
 	"golang.org/x/text/language"
 	"golang.org/x/tools/go/packages"
@@ -19,6 +20,24 @@ import (
 
 const tsgoInternalPrefix = "github.com/microsoft/typescript-go/internal/"
 
+func signatureHasUnexportedType(t types.Signature) bool {
+	if params := t.Params(); params != nil {
+		for i := range params.Len() {
+			ty := params.At(i).Type()
+
+			if ptrType, ok := ty.(*types.Pointer); ok {
+				ty = ptrType.Elem()
+			}
+			if named, ok := ty.(*types.Named); ok {
+				if !named.Obj().Exported() {
+					return true
+				}
+			}
+		}
+	}
+	return false
+}
+
 type ExtraShim struct {
 	ExtraFunctions  []string
 	ExtraMethods    map[string]([]string)
@@ -128,6 +147,10 @@ func main() {
 				// linking to functions with generics is not supported in go:linkname
 				return false
 			}
+			if signatureHasUnexportedType(*fn.Signature()) {
+				fmt.Fprintf(os.Stderr, "Skipping %s.%s: references unexported types\n", fn.Pkg().Name(), fn.Name())
+				return false
+			}
 			name := cases.Title(language.English, cases.NoLower).String(fn.Name())
 			emitGoLinknameDirective(name, fn)
 			shimBuilder.WriteString("func ")