diff --git a/helper/schema/field_reader_map.go b/helper/schema/field_reader_map.go
index d3ea401350..569cf9d915 100644
--- a/helper/schema/field_reader_map.go
+++ b/helper/schema/field_reader_map.go
@@ -56,8 +56,11 @@ func (r *MapFieldReader) readMap(k string) (FieldReadResult, error) {
 	prefix := k + "."
 	r.Map.Range(func(k, v string) bool {
 		if strings.HasPrefix(k, prefix) {
-			result[k[len(prefix):]] = v
-			resultSet = true
+			key := k[len(prefix):]
+			if key != "#" {
+				result[key] = v
+				resultSet = true
+			}
 		}
 
 		return true
diff --git a/helper/schema/field_reader_map_test.go b/helper/schema/field_reader_map_test.go
index cd4f6b9564..ae4e69b5ea 100644
--- a/helper/schema/field_reader_map_test.go
+++ b/helper/schema/field_reader_map_test.go
@@ -28,6 +28,7 @@ func TestMapFieldReader(t *testing.T) {
 				"listInt.0": "21",
 				"listInt.1": "42",
 
+				"map.#":   "2",
 				"map.foo": "bar",
 				"map.bar": "baz",
 
diff --git a/helper/schema/field_writer_map.go b/helper/schema/field_writer_map.go
index fd67963773..a9b38ac45c 100644
--- a/helper/schema/field_writer_map.go
+++ b/helper/schema/field_writer_map.go
@@ -170,6 +170,9 @@ func (w *MapFieldWriter) setMap(
 		}
 	}
 
+	// Set the count
+	w.result[k+".#"] = strconv.Itoa(len(vs))
+
 	return nil
 }
 
diff --git a/helper/schema/field_writer_map_test.go b/helper/schema/field_writer_map_test.go
index fa2e2fa2b7..ea87e6734d 100644
--- a/helper/schema/field_writer_map_test.go
+++ b/helper/schema/field_writer_map_test.go
@@ -107,6 +107,7 @@ func TestMapFieldWriter(t *testing.T) {
 			map[string]interface{}{"foo": "bar"},
 			false,
 			map[string]string{
+				"map.#":   "1",
 				"map.foo": "bar",
 			},
 		},
diff --git a/helper/schema/resource_data_test.go b/helper/schema/resource_data_test.go
index 92851c9bcc..fa0c18ca92 100644
--- a/helper/schema/resource_data_test.go
+++ b/helper/schema/resource_data_test.go
@@ -1641,8 +1641,10 @@ func TestResourceDataState(t *testing.T) {
 			State: &terraform.InstanceState{
 				Attributes: map[string]string{
 					"config_vars.#":     "2",
+					"config_vars.0.#":   "2",
 					"config_vars.0.foo": "bar",
 					"config_vars.0.bar": "bar",
+					"config_vars.1.#":   "1",
 					"config_vars.1.bar": "baz",
 				},
 			},
@@ -1669,7 +1671,9 @@ func TestResourceDataState(t *testing.T) {
 			Result: &terraform.InstanceState{
 				Attributes: map[string]string{
 					"config_vars.#":     "2",
+					"config_vars.0.#":   "1",
 					"config_vars.0.foo": "bar",
+					"config_vars.1.#":   "1",
 					"config_vars.1.baz": "bang",
 				},
 			},
@@ -2094,8 +2098,10 @@ func TestResourceDataState(t *testing.T) {
 				Attributes: map[string]string{
 					// TODO: broken, shouldn't bar be removed?
 					"config_vars.#":     "2",
+					"config_vars.0.#":   "2",
 					"config_vars.0.foo": "bar",
 					"config_vars.0.bar": "bar",
+					"config_vars.1.#":   "1",
 					"config_vars.1.bar": "baz",
 				},
 			},
@@ -2199,6 +2205,7 @@ func TestResourceDataState(t *testing.T) {
 
 			Result: &terraform.InstanceState{
 				Attributes: map[string]string{
+					"tags.#":    "1",
 					"tags.Name": "foo",
 				},
 			},
@@ -2289,6 +2296,57 @@ func TestResourceDataState(t *testing.T) {
 				},
 			},
 		},
+
+		// #23 Set of maps
+		{
+			Schema: map[string]*Schema{
+				"ports": &Schema{
+					Type:     TypeSet,
+					Optional: true,
+					Computed: true,
+					Elem: &Resource{
+						Schema: map[string]*Schema{
+							"index": &Schema{Type: TypeInt},
+							"uuids": &Schema{Type: TypeMap},
+						},
+					},
+					Set: func(a interface{}) int {
+						m := a.(map[string]interface{})
+						return m["index"].(int)
+					},
+				},
+			},
+
+			State: nil,
+
+			Diff: &terraform.InstanceDiff{
+				Attributes: map[string]*terraform.ResourceAttrDiff{
+					"ports.10.uuids.#": &terraform.ResourceAttrDiff{
+						NewComputed: true,
+					},
+				},
+			},
+
+			Set: map[string]interface{}{
+				"ports": []interface{}{
+					map[string]interface{}{
+						"index": 10,
+						"uuids": map[string]interface{}{
+							"80": "value",
+						},
+					},
+				},
+			},
+
+			Result: &terraform.InstanceState{
+				Attributes: map[string]string{
+					"ports.#":           "1",
+					"ports.10.index":    "10",
+					"ports.10.uuids.#":  "1",
+					"ports.10.uuids.80": "value",
+				},
+			},
+		},
 	}
 
 	for i, tc := range cases {
diff --git a/helper/schema/resource_test.go b/helper/schema/resource_test.go
index 845bd264d6..3c378673b7 100644
--- a/helper/schema/resource_test.go
+++ b/helper/schema/resource_test.go
@@ -157,6 +157,7 @@ func TestResourceApply_destroyCreate(t *testing.T) {
 		Attributes: map[string]string{
 			"id":        "foo",
 			"foo":       "42",
+			"tags.#":    "1",
 			"tags.Name": "foo",
 		},
 	}