1890–91 Royal Arsenal F.C. season

This was the club's first season as a professional side, with overwhelming support to do so from the players.

Their achievements in the previous season saw them granted direct admission to the first round proper of the FA Cup, marking their first full appearance in the competition.

After finishing as runners-up the previous season, they won the London Senior Cup for the first time.

Turning professional meant that they rescinded their membership of both London and Kent FAs, though support for the club continued to soar, with average attendances of 6,600, higher than half the teams in The Football League.

Players making their debut for Arsenal are shown in Bold, Goalkeepers are marked in Italics.