Mjallby Allmanna Idrottsforening, also known simply as Mjallby AIF, Mjallby or (especially locally) MAIF, is a Swedish professional football club based in Hallevik. The club is affiliated to Blekinge Fotbollforbund and play its home games at Strandvallen. The club colours, reflected in their crest and kit, are yellow and black. Formed on 1 April 1939, the club have played eight seasons in Sweden's highest football league Allsvenskan, the club's first season in the league was in 1980. The club are currently playing in Allsvenskan (top division). With nine seasons in the top division Allsvenskan, Mjallby AIF is the most successful football team from the province of Blekinge.
Former Sweden national football team players Christian Wilhelmsson and Mattias Asper began their careers at the club. Both players also ended their playing careers in Mjallby.