The 1905 MJFA season, also known as the 1905 MFA season, was the 14th season of the Metropolitan Junior Football Association (MJFA).
Port Rovers won the MJFA premiership for the first time, finishing first on the ladder with 15 wins from its 18 games.
Like the previous season in 1904, a total of ten teams competed in the MJFA. On 30 March 1905, prior to the start of the season, Boroondara merged with . Hawthorn retained its own name, but adopted Boroondara's colours of a black guernsey with a red sash.
The University Football Club, which had fielded a reserves team in the MJFA during the 1893 season, returned to the competition with a senior team.