diff --git a/.appveyor.yml b/.appveyor.yml
index 164e52319..9f0b472ad 100644
--- a/.appveyor.yml
+++ b/.appveyor.yml
@@ -2,16 +2,20 @@ environment:
 
     matrix:
         - TOXENV: py27-pip8
+        - TOXENV: py27-pip8.1.1
         - TOXENV: py27-pip9
         - TOXENV: py27-piplatest
         - TOXENV: py34-pip8
+        - TOXENV: py34-pip8.1.1
         - TOXENV: py34-pip9
         - TOXENV: py34-piplatest
-        - TOXENV: py35-pip9
         - TOXENV: py35-pip8
+        - TOXENV: py35-pip8.1.1
+        - TOXENV: py35-pip9
         - TOXENV: py35-piplatest
-        - TOXENV: py36-pip9
         - TOXENV: py36-pip8
+        - TOXENV: py36-pip8.1.1
+        - TOXENV: py36-pip9
         - TOXENV: py36-piplatest
 
 install:
diff --git a/piptools/writer.py b/piptools/writer.py
index 0194056c2..7fdc76e95 100644
--- a/piptools/writer.py
+++ b/piptools/writer.py
@@ -5,7 +5,7 @@
 from .click import unstyle
 from .io import AtomicSaver
 from .logging import log
-from .utils import comment, format_requirement, dedup, UNSAFE_PACKAGES
+from .utils import comment, dedup, format_requirement, key_from_req, UNSAFE_PACKAGES
 
 
 class OutputWriter(object):
@@ -96,7 +96,7 @@ def _iter_lines(self, results, unsafe_requirements, reverse_dependencies,
         for ireq in packages:
             line = self._format_requirement(
                 ireq, reverse_dependencies, primary_packages,
-                markers.get(ireq.req.name), hashes=hashes)
+                markers.get(key_from_req(ireq.req)), hashes=hashes)
             yield line
 
         if unsafe_requirements:
@@ -108,7 +108,7 @@ def _iter_lines(self, results, unsafe_requirements, reverse_dependencies,
                 req = self._format_requirement(ireq,
                                                reverse_dependencies,
                                                primary_packages,
-                                               marker=markers.get(ireq.req.name),
+                                               marker=markers.get(key_from_req(ireq.req)),
                                                hashes=hashes)
                 if not allow_unsafe:
                     yield comment('# {}'.format(req))
diff --git a/tox.ini b/tox.ini
index 41e3ac337..779132c05 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,9 +1,10 @@
 [tox]
-envlist = py{27,34,35,36,py}-pip{8,9,latest},flake8
+envlist = py{27,34,35,36,py}-pip{8,8.1.1,9,latest},flake8
 
 [testenv]
 deps =
     piplatest: pip
+    pip8.1.1: pip==8.1.1
     pip8: pip~=8.0
     pip9: pip~=9.0
     coverage