The Serbia international, who also won the Match POTM award, scored in five of his six league games in April, including the winners against Sheffield Wednesday and Sunderland.
"He's had a huge impact," managed Slavisa Jokanovic told the EFL website. "He showed the quality he has fighting with this team and he's doing a great job for us.
"We're very satisfied to have him and we hope he's going to play a big part in Fulham's promotion."
Mitrovic, meanwhile, added: "It feels great, I'm glad for the award, but I'm even happier that the team is doing well and keep winning games.
"We have one game to go before the end of the regular season, so we have to focus on this game to try and win and see what happens with Cardiff.
"Coming to Fulham has gone much better than I could have ever expected and I hope it can continue."
Fulham currently sit third in the Championship table, one point behind second-placed Cardiff City.