As far as I know, setuptools doesn't support using a list of strings in order to specify multiple authors. Your best bet is to list the authors in a single string:

author='Foo Bar, Spam Eggs',
author_email='foobar@baz.com, spameggs@joe.org',

I'm not sure if PyPI validates the author_email field, so you may run into trouble with that one. In any case, I would recommend you limit these to a single author and mention all contributors in the documentation or description.

Some sources:

This has been registered as a bug, actually, but it seems like support for multiple authors was not implemented. Here is an alternative solution. Here is an idea for how to provide a contact email for a project with multiple authors.

I'm sort of just piggybacking off of @modocache's answer, in case you want some specifics.

Throughout this answer, I'll be refering to a python3.6 version of the FOO-PYTHON-ENV\Lib\distutils\dist.py file

To reiterate, you cannot use a list in the author field. Here's why:

Spoiler: Two methods belonging to the DistributionMetadata class are the reason --

def _read_field(name):
value = msg[name]
if value == 'UNKNOWN':
return None
return value


def _read_list(name):
values = msg.get_all(name, None)
if values == []:
return None
return values

Here's where you'll hit an error if you try to stick a list in the author field:

class DistributionMetadata:


#*...(R E D A C T E D)...*#


def read_pkg_file(self, file):
"""Reads the metadata values from a file object."""
#*...(R E D A C T E D)...*#
# ####################################
# Note the usage of _read_field() here
# ####################################
self.name = _read_field('name')
self.version = _read_field('version')
self.description = _read_field('summary')
# we are filling author only.
self.author = _read_field('author')
self.maintainer = None
self.author_email = _read_field('author-email')
self.maintainer_email = None
self.url = _read_field('home-page')
self.license = _read_field('license')
#*...(R E D A C T E D)...*#
# ###################################
# Note the usage of _read_list() here
# ###################################
self.platforms = _read_list('platform')
self.classifiers = _read_list('classifier')
#*...(R E D A C T E D)...*#

& Here's the whole thing:

class DistributionMetadata:
"""Dummy class to hold the distribution meta-data: name, version,
author, and so forth.
"""


_METHOD_BASENAMES = ("name", "version", "author", "author_email",
"maintainer", "maintainer_email", "url",
"license", "description", "long_description",
"keywords", "platforms", "fullname", "contact",
"contact_email", "classifiers", "download_url",
# PEP 314
"provides", "requires", "obsoletes",
)


def __init__(self, path=None):
if path is not None:
self.read_pkg_file(open(path))
else:
self.name = None
self.version = None
self.author = None
self.author_email = None
self.maintainer = None
self.maintainer_email = None
self.url = None
self.license = None
self.description = None
self.long_description = None
self.keywords = None
self.platforms = None
self.classifiers = None
self.download_url = None
# PEP 314
self.provides = None
self.requires = None
self.obsoletes = None


def read_pkg_file(self, file):
"""Reads the metadata values from a file object."""
msg = message_from_file(file)


def _read_field(name):
value = msg[name]
if value == 'UNKNOWN':
return None
return value


def _read_list(name):
values = msg.get_all(name, None)
if values == []:
return None
return values


metadata_version = msg['metadata-version']
self.name = _read_field('name')
self.version = _read_field('version')
self.description = _read_field('summary')
# we are filling author only.
self.author = _read_field('author')
self.maintainer = None
self.author_email = _read_field('author-email')
self.maintainer_email = None
self.url = _read_field('home-page')
self.license = _read_field('license')


if 'download-url' in msg:
self.download_url = _read_field('download-url')
else:
self.download_url = None


self.long_description = _read_field('description')
self.description = _read_field('summary')


if 'keywords' in msg:
self.keywords = _read_field('keywords').split(',')


self.platforms = _read_list('platform')
self.classifiers = _read_list('classifier')


# PEP 314 - these fields only exist in 1.1
if metadata_version == '1.1':
self.requires = _read_list('requires')
self.provides = _read_list('provides')
self.obsoletes = _read_list('obsoletes')
else:
self.requires = None
self.provides = None
self.obsoletes = None

Consider using flit to build the package, as this build system supports multiple authors and maintainers. Store this metadata in pyproject.toml as follows:

[build-system]
requires = ["flit_core >=3.2,<4"]
build-backend = "flit_core.buildapi"


[project]
...
authors = [
{name = "First1 Last1", email = "name1@foo.bar"},
{name = "First2 Last2", email = "name2@foo.bar"},
]
maintainers = [
{name = "First1 Last1", email = "name1@foo.bar"},
{name = "First2 Last2", email = "name2@foo.bar"},
]