--- /dev/null
+diff --git a/setuptools/command/easy_install.py b/setuptools/command/easy_install.py
+index df1655b..24c34e5 100755
+--- a/setuptools/command/easy_install.py
++++ b/setuptools/command/easy_install.py
+@@ -1885,7 +1885,7 @@ class CommandSpec(list):
+ return param
+ if isinstance(param, list):
+ return cls(param)
+- if param is None:
++ if param is None or os.environ.get('__PYVENV_LAUNCHER__'):
+ return cls.from_environment()
+ # otherwise, assume it's a string.
+ return cls.from_string(param)