Four members of Marc Skinner's squad are vying for your selection in our poll, following a period in which the Reds wrapped up Champions League qualification for next season and played in a third consecutive Adobe Women's FA Cup final.
That was before United headed to Portugal and finished runners-up at the inaugural World Sevens tournament, which did not factor into the thinking behind the quartet that you can pick from towards the bottom of this article.
Scroll down for a run-through of the nominees, and that all-important poll...
GRACE CLINTON
The England midfielder played every minute of our three matches in May - against Manchester City, Arsenal and Chelsea - and her highlight of the month was undoubtedly a brilliant headed goal in the derby at Old Trafford.