diff --git a/.changelog/28865.txt b/.changelog/28865.txt
new file mode 100644
index 00000000000..aa592fe875f
--- /dev/null
+++ b/.changelog/28865.txt
@@ -0,0 +1,3 @@
+```release-note:bug
+resource/aws_sagemaker_model_package_group_policy: Improve refresh to avoid unnecessary diffs in `resource_policy`
+```
diff --git a/internal/service/sagemaker/model_package_group_policy.go b/internal/service/sagemaker/model_package_group_policy.go
index 29c1182b053..2d634bcf1ff 100644
--- a/internal/service/sagemaker/model_package_group_policy.go
+++ b/internal/service/sagemaker/model_package_group_policy.go
@@ -32,10 +32,11 @@ func ResourceModelPackageGroupPolicy() *schema.Resource {
 				ForceNew: true,
 			},
 			"resource_policy": {
-				Type:             schema.TypeString,
-				Required:         true,
-				ValidateFunc:     validation.StringIsJSON,
-				DiffSuppressFunc: verify.SuppressEquivalentPolicyDiffs,
+				Type:                  schema.TypeString,
+				Required:              true,
+				ValidateFunc:          validation.StringIsJSON,
+				DiffSuppressFunc:      verify.SuppressEquivalentPolicyDiffs,
+				DiffSuppressOnRefresh: true,
 				StateFunc: func(v interface{}) string {
 					json, _ := structure.NormalizeJsonString(v)
 					return json
@@ -49,7 +50,6 @@ func resourceModelPackageGroupPolicyPut(d *schema.ResourceData, meta interface{}
 	conn := meta.(*conns.AWSClient).SageMakerConn()
 
 	policy, err := structure.NormalizeJsonString(d.Get("resource_policy").(string))
-
 	if err != nil {
 		return fmt.Errorf("policy (%s) is invalid JSON: %w", d.Get("resource_policy").(string), err)
 	}
@@ -87,7 +87,6 @@ func resourceModelPackageGroupPolicyRead(d *schema.ResourceData, meta interface{
 	d.Set("model_package_group_name", d.Id())
 
 	policyToSet, err := verify.PolicyToSet(d.Get("resource_policy").(string), aws.StringValue(mpg.ResourcePolicy))
-
 	if err != nil {
 		return err
 	}