Theodoros II Doukas Laskaris or Theodore Ducas Lascaris (Greek: Θεόδωρος Β΄ Δούκας Λάσκαρις) was Emperor of Nicaea from 1254 to 1258.
Theodore II Doukas Laskaris was the only son of Emperor John III Doukas Vatatzes and Eirene Laskarina, the daughter of Emperor Theodore I Laskaris and Anna Angelina, a daughter of Emperor Alexios III Angelos and Euphrosyne Doukaina Kamaterina. Theodore was born in late 1221 or early 1222, reportedly on the very day his father ascended the throne.
On the death of John III on November 4, 1254, Theodore II was acclaimed emperor by the army and the court, but was crowned only after the appointment of a new patriarch, Arsenios Autoreianos, in 1255.
The emperor died on August 16, 1258, leaving George Mouzalon as the regent for his minor son John IV Laskaris who was seven years old at the time.