diff --git a/.coveragerc b/.coveragerc
index fac1b07a..5a1a08f9 100644
--- a/.coveragerc
+++ b/.coveragerc
@@ -1,7 +1,11 @@
 [run]
 branch = True
-omit = attr/_compat.py
 source = attr
 
+[paths]
+source =
+   src/attr
+   .tox/*/lib/python*/site-packages/attr
+   .tox/pypy/site-packages/attr
 [report]
 show_missing = True
diff --git a/.gitignore b/.gitignore
index b4f9c71c..321aae50 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,5 +1,5 @@
 .tox
-.coverage
+.coverage*
 *.pyc
 *.egg-info
 docs/_build/
diff --git a/docs/conf.py b/docs/conf.py
index ef046966..cacf3c2d 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -90,7 +90,7 @@ copyright = u'2015{0}, Hynek Schlawack'.format(
 # built documents.
 #
 # The short X.Y version.
-release = find_version("../attr/__init__.py")
+release = find_version("../src/attr/__init__.py")
 version = release.rsplit(u".", 1)[0]
 # The full version, including alpha/beta/rc tags.
 
diff --git a/setup.py b/setup.py
index e6f7814b..3ba74784 100644
--- a/setup.py
+++ b/setup.py
@@ -8,8 +8,8 @@ from setuptools import setup, find_packages
 ###############################################################################
 
 NAME = "attrs"
-PACKAGES = find_packages(exclude=["tests*"])
-META_PATH = os.path.join("attr", "__init__.py")
+PACKAGES = find_packages(where="src", exclude=["tests*"])
+META_PATH = os.path.join("src", "attr", "__init__.py")
 KEYWORDS = ["class", "attribute", "boilerplate"]
 CLASSIFIERS = [
     "Development Status :: 5 - Production/Stable",
@@ -75,6 +75,7 @@ if __name__ == "__main__":
         keywords=KEYWORDS,
         long_description=read("README.rst"),
         packages=PACKAGES,
+        package_dir={"": "src"},
         zip_safe=False,
         classifiers=CLASSIFIERS,
         install_requires=INSTALL_REQUIRES,
diff --git a/attr/__init__.py b/src/attr/__init__.py
similarity index 100%
rename from attr/__init__.py
rename to src/attr/__init__.py
diff --git a/attr/_compat.py b/src/attr/_compat.py
similarity index 100%
rename from attr/_compat.py
rename to src/attr/_compat.py
diff --git a/attr/_config.py b/src/attr/_config.py
similarity index 100%
rename from attr/_config.py
rename to src/attr/_config.py
diff --git a/attr/_funcs.py b/src/attr/_funcs.py
similarity index 100%
rename from attr/_funcs.py
rename to src/attr/_funcs.py
diff --git a/attr/_make.py b/src/attr/_make.py
similarity index 100%
rename from attr/_make.py
rename to src/attr/_make.py
diff --git a/attr/filters.py b/src/attr/filters.py
similarity index 100%
rename from attr/filters.py
rename to src/attr/filters.py
diff --git a/attr/validators.py b/src/attr/validators.py
similarity index 100%
rename from attr/validators.py
rename to src/attr/validators.py
diff --git a/tox.ini b/tox.ini
index 92391dbb..c1880229 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist = py26, py27, py33, py34, py35, pypy, flake8, manifest, docs
+envlist = coverage-clean, py26, py27, py33, py34, py35, pypy, flake8, manifest, docs, coverage-report
 
 [testenv]
 passenv = TERM  # ensure colors
@@ -8,15 +8,14 @@ deps =
     pytest>=2.7.2  # see https://github.com/hynek/attrs/issues/14
     zope.interface
 commands =
-    coverage run {envbindir}/py.test tests
-    coverage report -m
+    coverage run --parallel -m pytest tests
 
 
 [testenv:flake8]
 basepython = python2.7
 deps =
     flake8
-commands = flake8 attr tests setup.py
+commands = flake8 src tests setup.py
 
 
 [testenv:docs]
@@ -37,3 +36,16 @@ deps =
     check-manifest
 commands =
     check-manifest
+
+[testenv:coverage-clean]
+deps = coverage
+skip_install = true
+commands = coverage erase
+
+[testenv:coverage-report]
+basepython = python3.5
+deps = coverage
+skip_install = true
+commands =
+    coverage combine
+    coverage report