The 18-year-old was superb for Coventry in August, having moved to the League One outfit on a youth loan from Premier League side Newcastle until January 2016 in late July.
The teenager scored five goals in as many league games for Tony Mowbray’s side last month, who are fifth in the League One table at the moment with 10 points from five matches.
Armstrong is delighted to have had his efforts for Coventry recognised and has posted the following message on Twitter after winning the League One Player of the Month award.
Honoured to get this award! Couldn't of got this without my teammates! Thank you for all the messages pic.twitter.com/UPChkFGQvf— AdamArma (@AdamArma9) September 4, 2015
Coventry are back in action on Sunday afternoon, when they take on Burton Albion away from home at the Pirelli Stadium in League One.
The Sky Blues will be confident of picking up all three points from the match, as they maintain their challenge for a top-six finish in the league table this season.