The Second Swedish Crusade was a military expedition by the Kingdom of Sweden into Tavastia (Häme) in southern Finland described by Erik's Chronicle. According to the chronicle, the Swedes defeated the pagan Tavastians under the leadership of Birger Jarl, and started building a castle in Tavastia.
The expedition has traditionally been dated to 1249–1250 based on the chronology of the chronicle. However, some researchers have suggested that the expedition instead took place already in 1238–1239, shortly after the Tavastian uprising and before the Battle of the Neva against the Novgorod Republic. The castle that the Swedes began constructing during the expedition has traditionally been identified as Häme Castle, but it may also have been the older Hakoinen Castle.