diff --git a/assert/assertions.go b/assert/assertions.go
index 166f637..176e9dd 100644
--- a/assert/assertions.go
+++ b/assert/assertions.go
@@ -1955,8 +1955,13 @@ func diff(expected interface{}, actual interface{}) string {
 		e = spewConfigStringerEnabled.Sdump(expected)
 		a = spewConfigStringerEnabled.Sdump(actual)
 	default:
-		e = spewConfig.Sdump(expected)
-		a = spewConfig.Sdump(actual)
+		if hasStringer(et) {
+			e = spewConfigStringerEnabled.Sdump(expected)
+			a = spewConfigStringerEnabled.Sdump(actual)
+		} else {
+			e = spewConfig.Sdump(expected)
+			a = spewConfig.Sdump(actual)
+		}
 	}
 
 	diff, _ := difflib.GetUnifiedDiffString(difflib.UnifiedDiff{
@@ -1972,6 +1977,25 @@ func diff(expected interface{}, actual interface{}) string {
 	return "\n\nDiff:\n" + diff
 }
 
+var stringerType = reflect.TypeOf((*fmt.Stringer)(nil)).Elem()
+
+// hasStringer reports whether t, or the element type of a slice or array,
+// implements fmt.Stringer. It lets diff render such values through the
+// Stringer-enabled spew config, so a named string like peer.ID is shown by its
+// String output instead of its raw bytes. This influences diff presentation
+// only: equality is decided by ObjectsAreEqual and is unaffected, and the
+// default spew config keeps DisableMethods for every other type.
+func hasStringer(t reflect.Type) bool {
+	if t.Implements(stringerType) {
+		return true
+	}
+	switch t.Kind() {
+	case reflect.Slice, reflect.Array:
+		return t.Elem().Implements(stringerType)
+	}
+	return false
+}
+
 func isFunction(arg interface{}) bool {
 	if arg == nil {
 		return false
diff --git a/assert/assertions_test.go b/assert/assertions_test.go
index 11642e0..16b819c 100644
--- a/assert/assertions_test.go
+++ b/assert/assertions_test.go
@@ -2902,6 +2902,12 @@ func (d *diffTestingStruct) String() string {
 	return d.A
 }
 
+type diffTestingStringer string
+
+func (id diffTestingStringer) String() string {
+	return "stringer:" + string(id)
+}
+
 func TestDiff(t *testing.T) {
 	t.Parallel()
 
@@ -3036,6 +3042,24 @@ Diff:
 		time.Date(2020, 9, 25, 0, 0, 0, 0, time.UTC),
 	)
 	Equal(t, expected, actual)
+
+	expected = `
+
+Diff:
+--- Expected
++++ Actual
+@@ -2,3 +2,3 @@
+  (assert.diffTestingStringer) (len=3) stringer:one,
+- (assert.diffTestingStringer) (len=3) stringer:two
++ (assert.diffTestingStringer) (len=5) stringer:three
+ }
+`
+
+	actual = diff(
+		[]diffTestingStringer{"one", "two"},
+		[]diffTestingStringer{"one", "three"},
+	)
+	Equal(t, expected, actual)
 }
 
 func TestTimeEqualityErrorFormatting(t *testing.T) {