diff --git a/resolution/module-resolver.go b/resolution/module-resolver.go
index da6876d..b084fb6 100644
--- a/resolution/module-resolver.go
+++ b/resolution/module-resolver.go
@@ -20,9 +20,9 @@ type ModuleResolver struct {
 	lithiaSourceGlob    string
 }
 
-func DefaultModuleResolver() ModuleResolver {
+func DefaultModuleResolver(importRoots ...string) ModuleResolver {
 	return ModuleResolver{
-		externalImportRoots: defaultImportRoots(),
+		externalImportRoots: defaultImportRoots(importRoots...),
 		defaultPackageName:  "root",
 		manifestName:        "Potfile",
 		manifestSearchPaths: []string{".", "..", "../..", "../../..", "../../../.."},
@@ -52,8 +52,8 @@ type PackageManifest struct {
 	Path string
 }
 
-func defaultImportRoots() []string {
-	roots := []string{}
+func defaultImportRoots(importRoots ...string) []string {
+	roots := importRoots
 	if path, ok := os.LookupEnv("LITHIA_LOCALS"); ok {
 		roots = append(roots, path)
 	}
diff --git a/runtime/interpreter.go b/runtime/interpreter.go
index ef51a68..355e8e0 100644
--- a/runtime/interpreter.go
+++ b/runtime/interpreter.go
@@ -18,7 +18,7 @@ type Interpreter struct {
 
 func NewInterpreter(referenceFile string, importRoots ...string) *Interpreter {
 	inter := &Interpreter{
-		Resolver:            resolution.DefaultModuleResolver(),
+		Resolver:            resolution.DefaultModuleResolver(importRoots...),
 		Parser:              parser.NewParser(),
 		Modules:             make(map[ast.ModuleName]*RuntimeModule),
 		ExternalDefinitions: make(map[ast.ModuleName]ExternalDefinition),
diff --git a/runtime/runtime-stdlib_test.go b/runtime/runtime-stdlib_test.go
index 5c14703..c16bc18 100644
--- a/runtime/runtime-stdlib_test.go
+++ b/runtime/runtime-stdlib_test.go
@@ -11,7 +11,7 @@ import (
 
 func TestStdlib(t *testing.T) {
 	pathToStdlib := "../stdlib"
-	inter := r.NewInterpreter(pathToStdlib)
+	inter := r.NewInterpreter(pathToStdlib, "../stdlib")
 	mockOS := &mockExternalOS{
 		calledExitCode: -1,
 		env:            map[string]string{"LITHIA_TESTS": "1"},