The American World Cup winner came top of a survey conducted amongst women's football experts by the broadcaster.
Mewis has made a huge impact since joining City from North Carolina Courage last summer.
Her energy, drive and technical qualities helped Gareth Taylor’s side lift the 2020 Women’s FA Cup last November.
And the 28-year-old has also been instrumental in helping City’s quest for success in this season’s FA Women’s Super League, UEFA Women’s Champions League.
"It's a huge honour, I know there were a lot of incredible players on the list. I'm honoured and incredibly grateful to my team mates who are the whole reason this is possible," Mewis said.
"The WSL has been incredible and really competitive and is only growing as is women's football everywhere which is so exciting.
"City have been incredible as has the league and it's such a great time for the game globally."
The strength of the FA Women's Super League was demonstrated with the top five comprising of players from the English top flight.
Mewis was joined in the top five by her City team-mate Lucy Bronze, with the defender and current FIFA best women’s player ranked in fifth spot with Sam Kerr, Vivianne Miedema and Pernille Harder making up the quintet.