1905–06 in European association football leagues

The 1906 SEGAS Championship was the first organised Hellenic Amateur Athletic Association competition to take place in mainland Greece. It took place in March 1906. It was not organised by the HFF and as such it is not recognised by it.

The 1905–06 Scottish Division One season was won by Celtic by six points over nearest rival Heart of Midlothian.

The Netherlands Football League Championship 1905–1906 was contested by sixteen teams participating in two divisions. The national champion would be determined by a play-off featuring the winners of the eastern and western football division of the Netherlands. HBS Craeyenhout won this year's championship by beating PW 3-2 and 4–2.

The 1905–06 İstanbul Football League season was the second season of the league. Cadi-Keuy FC won the league for the first time.

The 1906 German football championship was the fourth competition for the national championship of Germany. Held under the auspices of the German Football Association (DFB), eight teams competed for the title. For the first time only champions of regional football associations were admitted to the championship, excluding champions of local associations such as the Verband Magdeburger Ballspielvereine (Association of Magdeburg ballgame clubs). An exception was the situation in Berlin where two associations — the Verband Berliner Ballspielvereine (VBB) and the Märkischer Fußballbund (MFB) — existed. Both their champions were admitted, as were defending champions Berliner TuFC Union 92. This led to three teams from Berlin competing in the final tournament.

The 1905–06 Irish League was the 16th edition of the Irish League, the highest level of league competition in Irish football.

Statistics of Swiss Super League in the 1905–06 season.

Final standings of the Hungarian League 1905 season. The championship title of the unbeaten Postás was withdrawn half year after the last match, due to a bribery scandal.

Statistics of Belgian First Division in the 1905–06 season.

The 1906 Prima Categoria season was won by Milan.