Apaj; died after 1239) was a Hungarian baron in the first third of the 13th century, who served as Ban of Slavonia from 1237 to 1239, during the reign of Béla IV of Hungary.

[3] Apaj possessed landholdings in Križevci County (Körös) in the area between Legrad and Rasinja (present-day in Croatia).

According to Croatian historian Baltazar Adam Krčelić, Apaj handed over the fort to the Knights Templar in exchange for his spiritual salvation.

His surviving seal from 1239 is one of the earliest rare examples in Hungary which depicts a mounted knight.

[4] His lands were inherited by his only son Apaj (II), who was also referred to as patron of the Sárvár family monastery in 1270.