diff --git a/README.md b/README.md
index 975f6d0..de1ca3d 100644
--- a/README.md
+++ b/README.md
@@ -37,9 +37,13 @@ type Sample struct {
 
 	Slice       []string       `default:"[]"`
 	SliceByJSON []int          `default:"[1, 2, 3]"` // Supports JSON
-	Map         map[string]int `default:"{}"`
-	MapByJSON   map[string]int `default:"{\"foo\": 123}"`
 
+	Map                 map[string]int `default:"{}"`
+	MapByJSON           map[string]int `default:"{\"foo\": 123}"`
+	MapOfStruct         map[string]OtherStruct
+	MapOfPtrStruct      map[string]*OtherStruct
+	MapOfStructWithTag  map[string]OtherStruct `default:"{\"Key1\": {\"Foo\":123}}"`
+    
 	Struct    OtherStruct  `default:"{}"`
 	StructPtr *OtherStruct `default:"{\"Foo\": 123}"`
 
diff --git a/defaults.go b/defaults.go
index d4baf0f..61856e7 100644
--- a/defaults.go
+++ b/defaults.go
@@ -168,6 +168,31 @@ func setField(field reflect.Value, defaultVal string) error {
 				return err
 			}
 		}
+	case reflect.Map:
+		for _, e := range field.MapKeys() {
+			var v = field.MapIndex(e)
+			var baseVal interface{}
+			switch v.Kind() {
+			case reflect.Ptr:
+				baseVal = v.Elem().Interface()
+			default:
+				baseVal = v.Interface()
+			}
+			ref := reflect.New(reflect.TypeOf(baseVal))
+			ref.Elem().Set(reflect.ValueOf(baseVal))
+			err := Set(ref.Interface())
+			if err == nil || err == errInvalidType {
+				var newVal reflect.Value
+				if v.Kind() == reflect.Ptr {
+					newVal = reflect.ValueOf(ref.Interface())
+				} else {
+					newVal = reflect.ValueOf(ref.Elem().Interface())
+				}
+				field.SetMapIndex(e, newVal)
+			} else {
+				return err
+			}
+		}
 	}
 
 	return nil
@@ -187,6 +212,8 @@ func shouldInitializeField(field reflect.Value, tag string) bool {
 		}
 	case reflect.Slice:
 		return field.Len() > 0 || tag != ""
+	case reflect.Map:
+		return field.Len() > 0 || tag != ""
 	}
 
 	return tag != ""
diff --git a/defaults_test.go b/defaults_test.go
index 90f185d..5bfba7b 100644
--- a/defaults_test.go
+++ b/defaults_test.go
@@ -115,7 +115,12 @@ type Sample struct {
 	StructWithJSON    Struct         `default:"{\"Foo\": 123}"`
 	StructPtrWithJSON *Struct        `default:"{\"Foo\": 123}"`
 	MapWithJSON       map[string]int `default:"{\"foo\": 123}"`
-	SliceWithJSON     []string       `default:"[\"foo\"]"`
+
+	MapOfPtrStruct     map[string]*Struct
+	MapOfStruct        map[string]Struct
+	MapOfStructWithTag map[string]Struct `default:"{\"Struct3\": {\"Foo\":123}}"`
+
+	SliceWithJSON []string `default:"[\"foo\"]"`
 
 	Empty string `default:""`
 
@@ -203,6 +208,13 @@ func TestInit(t *testing.T) {
 		NonInitialStruct:           Struct{Foo: 123},
 		NonInitialStructPtr:        &Struct{Foo: 123},
 		DeepSliceOfStructWithNoTag: [][][]Struct{{{{Foo: 123}}}},
+		MapOfStruct: map[string]Struct{
+			"Struct1": {Foo: 1},
+		},
+		MapOfPtrStruct: map[string]*Struct{
+			"Struct1": {Foo: 1},
+			"Struct2": {Bar: 5},
+		},
 	}
 
 	if err := Set(sample); err != nil {
@@ -560,6 +572,69 @@ func TestInit(t *testing.T) {
 		}
 	})
 
+	t.Run("map of struct", func(t *testing.T) {
+		if sample.MapOfStruct == nil {
+			t.Errorf("it should not unset an initiated map")
+		}
+		if len(sample.MapOfStruct) != 1 {
+			t.Errorf("it should not override an initiated map")
+		}
+		if sample.MapOfStruct["Struct1"].Foo != 1 {
+			t.Errorf("it should not override Foo field in Struct1 item")
+		}
+		if sample.MapOfStruct["Struct1"].Bar != 456 {
+			t.Errorf("it should set default for Bar field in Struct1 item")
+		}
+		if sample.MapOfStruct["Struct1"].WithDefault != "foo" {
+			t.Errorf("it should set default for WithDefault field in Struct1 item")
+		}
+	})
+
+	t.Run("map of ptr struct", func(t *testing.T) {
+		if sample.MapOfPtrStruct == nil {
+			t.Errorf("it should not unset an initiated map")
+		}
+		if len(sample.MapOfPtrStruct) != 2 {
+			t.Errorf("it should not override an initiated map")
+		}
+		if sample.MapOfPtrStruct["Struct1"].Foo != 1 {
+			t.Errorf("it should not override Foo field in Struct1 item")
+		}
+		if sample.MapOfPtrStruct["Struct1"].Bar != 456 {
+			t.Errorf("it should set default for Bar field in Struct1 item")
+		}
+		if sample.MapOfPtrStruct["Struct1"].WithDefault != "foo" {
+			t.Errorf("it should set default for WithDefault field in Struct1 item")
+		}
+		if sample.MapOfPtrStruct["Struct2"].Foo != 0 {
+			t.Errorf("it should not override Foo field in Struct2 item")
+		}
+		if sample.MapOfPtrStruct["Struct2"].Bar != 456 {
+			t.Errorf("it should using setter to set default for Bar field in a Struct2 item")
+		}
+		if sample.MapOfPtrStruct["Struct2"].WithDefault != "foo" {
+			t.Errorf("it should set default for WithDefault field in Struct2 item")
+		}
+	})
+
+	t.Run("map of struct with tag", func(t *testing.T) {
+		if sample.MapOfStructWithTag == nil {
+			t.Errorf("it should set default")
+		}
+		if len(sample.MapOfStructWithTag) != 1 {
+			t.Errorf("it should set default with correct value")
+		}
+		if sample.MapOfStructWithTag["Struct3"].Foo != 123 {
+			t.Errorf("it should set default with correct value (Foo)")
+		}
+		if sample.MapOfStructWithTag["Struct1"].Bar != 0 {
+			t.Errorf("it should set default with correct value (Bar)")
+		}
+		if sample.MapOfStructWithTag["Struct1"].WithDefault != "" {
+			t.Errorf("it should set default with correct value (WithDefault)")
+		}
+	})
+
 	t.Run("opt-out", func(t *testing.T) {
 		if sample.NoDefault != nil {
 			t.Errorf("it should not be set")