The second Battle of Dorylaeum took place near Dorylaeum in October 1147, during the Second Crusade. It was not a single clash but consisted of a series of encounters over a number of days. The German crusader forces of Conrad III were defeated by the Seljuk Turks led by Sultan Mesud I.

The Seljuk dynasty, or Seljukids ( SEL-chuuk; Persian: آل سلجوق Al-e Saljuq, alternatively spelled as Seljuqs or Saljuqs), also known as Seljuk Turks, Seljuk Turkomans or the Saljuqids , was an Oghuz Turkic Sunni Muslim dynasty that gradually became Persianate and contributed to the Turco-Persian tradition in the medieval Middle East and Central Asia. The Seljuks established both the Seljuk Empire and the Sultanate of Rum, which at their heights stretched from Iran to Anatolia, and were targets of the First Crusade.