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)