diff --git setup.py setup.py
index 26f052b..e63f1b5 100755
--- setup.py
+++ setup.py
@@ -54,7 +54,7 @@ dependency resolution is disabled.
 
     from twisted.python.dist import (
         STATIC_PACKAGE_METADATA, getDataFiles, getExtensions, getAllScripts,
-        getPackages, setup)
+        getPackages, setup, EXTRAS_REQUIRE)
 
     scripts = getAllScripts()
 
@@ -62,6 +62,7 @@ dependency resolution is disabled.
         packages=getPackages('twisted'),
         conditionalExtensions=getExtensions(),
         scripts=scripts,
+        extras_require=EXTRAS_REQUIRE,
         data_files=getDataFiles('twisted'),
         **STATIC_PACKAGE_METADATA))
 
diff --git twisted/python/dist.py twisted/python/dist.py
index 9566039..c97bf3f 100644
--- twisted/python/dist.py
+++ twisted/python/dist.py
@@ -50,6 +50,29 @@ twisted_subprojects = ["conch", "lore", "mail", "names",
                        "words"]
 
 
+# extras_require is a dictionary of items that can be passed to setup.py
+# to install optional dependencies. For example, to install the optional
+# dev dependencies one would type `pip install -e . "twisted[dev]"`
+EXTRAS_REQUIRE = {
+    'docs': ['sphinx >= 1.2.2',
+             'pydoctor >= 0.5'],
+    'dev': ['twistedchecker >= 0.2.0',
+            'pyflakes >= 0.8.1',
+            'twisted-dev-tools >= 0.0.2'],
+    'conch': ['gmpy',
+              'pycrypto',
+              'pyasn1',
+              'pyopenssl'],
+    'subunit' : ['python-subunit'],
+    'soap': ['soappy'],
+    'windows': ['pywin32'],
+    'cocoa': ['pyobjc'],
+    'serial': ['pyserial'],
+    'gtk': ['PyGTK'],
+    'pam': ['pam'],
+    'wx': ['wxPython']
+}
+
 
 class ConditionalExtension(Extension):
     """
diff --git twisted/topfiles/3696.misc twisted/topfiles/3696.misc
new file mode 100644
index 0000000..78e79d4
--- /dev/null
+++ twisted/topfiles/3696.misc
@@ -0,0 +1 @@
+Optional dependencies can be installed using the extra_requires facility provided by setuptools
\ No newline at end of file