--- a/testing/mozharness/mozharness/base/python.py
+++ b/testing/mozharness/mozharness/base/python.py
@@ -216,19 +216,16 @@ class VirtualenvMixin(object):
                 self.fatal("Must specify module and/or requirements")
             pip = self.query_python_path("pip")
             if c.get("verbose_pip"):
                 command = [pip, "-v", "install"]
             else:
                 command = [pip, "install"]
             if no_deps:
                 command += ["--no-deps"]
-            virtualenv_cache_dir = c.get("virtualenv_cache_dir", os.path.join(venv_path, "cache"))
-            if virtualenv_cache_dir:
-                command += ["--download-cache", virtualenv_cache_dir]
             # To avoid timeouts with our pypi server, increase default timeout:
             # https://bugzilla.mozilla.org/show_bug.cgi?id=1007230#c802
             command += ['--timeout', str(c.get('pip_timeout', 120))]
             for requirement in requirements:
                 command += ["-r", requirement]
             if c.get('find_links') and not c["pip_index"]:
                 command += ['--no-index']
             for opt in global_options: