Inside where the py_library() is generated for each specified requirement, the import path is specified as "." (https://github.com/bazelbuild/rules_python/blob/master/rules_python/whl.py#L149). While this works for most packages, not all packages have the python module in the top level of the whl. For example, the tensorflow python module is inside tensorfow-<version_info>.whl/tensorfow-<version_info>.data/purelib/tensorflow. Because of this, import tensorflow will fail in a py_binary that has requirement("tensorflow"). What I believe rules_python/whl.py should be doing is to check whether the top-level folders have an __init__.py file inside of them, and if not, search the directory tree until it finds them.