diff --git a/helper/schema/field_reader_diff.go b/helper/schema/field_reader_diff.go
index 7a072fc0e..807abfdc2 100644
--- a/helper/schema/field_reader_diff.go
+++ b/helper/schema/field_reader_diff.go
@@ -69,6 +69,12 @@ func (r *DiffFieldReader) readMap(
 		resultSet = true
 	}
 
+	// Determine what element type the map contains, defaulting to string
+	elemType := TypeString
+	if et, ok := schema.Elem.(ValueType); ok {
+		elemType = et
+	}
+
 	// Next, read all the elements we have in our diff, and apply
 	// the diff to our result.
 	prefix := strings.Join(address, ".") + "."
@@ -89,7 +95,20 @@ func (r *DiffFieldReader) readMap(
 			continue
 		}
 
-		result[k] = v.New
+		// Replace the new value with one of the correct Elem type if needed.
+		// We don't supported arbitrarily nested schemas, so we can only handle
+		// the primitive types here.
+		var vNew interface{} = v.New
+		switch elemType {
+		case TypeBool, TypeInt, TypeFloat:
+			v, err := stringToPrimitive(v.New, false, &Schema{Type: elemType})
+			if err != nil {
+				return FieldReadResult{}, err
+			}
+			vNew = v
+		}
+
+		result[k] = vNew
 	}
 
 	var resultVal interface{}
diff --git a/helper/schema/resource_data_test.go b/helper/schema/resource_data_test.go
index c154e403f..40646dd7d 100644
--- a/helper/schema/resource_data_test.go
+++ b/helper/schema/resource_data_test.go
@@ -2983,7 +2983,7 @@ func TestResourceData_nonStringValuesInMap(t *testing.T) {
 					},
 					"boolMap.boolField": &terraform.ResourceAttrDiff{
 						Old: "",
-						New: "1",
+						New: "true",
 					},
 				},
 			},
@@ -2995,7 +2995,7 @@ func TestResourceData_nonStringValuesInMap(t *testing.T) {
 			Schema: map[string]*Schema{
 				"intMap": &Schema{
 					Type:     TypeMap,
-					Elem:     TypeBool,
+					Elem:     TypeInt,
 					Optional: true,
 				},
 			},