diff --git a/CHANGELOG.md b/CHANGELOG.md
index f972461..29f0fbb 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 0.12.2+5
+
+* Remove the dependency on the `collection` package.
+
 ## 0.12.2+4
 
 * Add an example of using command-line arguments to the README.
diff --git a/lib/src/arg_parser.dart b/lib/src/arg_parser.dart
index 8337c42..e7f728c 100644
--- a/lib/src/arg_parser.dart
+++ b/lib/src/arg_parser.dart
@@ -4,7 +4,7 @@
 
 library args.src.arg_parser;
 
-import 'package:collection/wrappers.dart';
+import 'dart:collection';
 
 import 'arg_results.dart';
 import 'option.dart';
diff --git a/lib/src/arg_results.dart b/lib/src/arg_results.dart
index 15fb5bb..6be2de4 100644
--- a/lib/src/arg_results.dart
+++ b/lib/src/arg_results.dart
@@ -4,7 +4,7 @@
 
 library args.src.arg_results;
 
-import 'package:collection/wrappers.dart';
+import 'dart:collection';
 
 import 'arg_parser.dart';
 
diff --git a/lib/src/option.dart b/lib/src/option.dart
index b2292db..4045bce 100644
--- a/lib/src/option.dart
+++ b/lib/src/option.dart
@@ -4,7 +4,7 @@
 
 library args.src.option;
 
-import 'package:collection/wrappers.dart';
+import 'dart:collection';
 
 /// Creates a new [Option].
 ///
diff --git a/pubspec.yaml b/pubspec.yaml
index fdf99c0..0af927d 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,14 +1,12 @@
 name: args
-version: 0.12.2+5
+version: 0.12.2+6
 author: "Dart Team <misc@dartlang.org>"
 homepage: https://github.com/dart-lang/args
 description: >
  Library for defining parsers for parsing raw command-line arguments into
  a set of options and values using GNU and POSIX style options.
 
-dependencies:
-  collection: ">=0.9.0 <2.0.0"
 dev_dependencies:
   unittest: ">=0.11.5 <0.12.0"
 environment:
-  sdk: ">=1.0.0 <2.0.0"
+  sdk: ">=1.4.0 <2.0.0"