Konstantin Kastrioti

Konstantin Kastrioti or Konstantin Kastrioti Mazarek (Latin: Constantinus Castriotus) (died 1390) was a noble man in Albania in 14th century, a member of Kastrioti family.

Konstanin's father was Pal Kastrioti who had three sons: Konstantin[A], Aleksa and Gjon Kastrioti who was Skanderbeg's father. Aleksa Kastrioti controlled three villages.

According to du Cange and some other authors, Konstantin was a vasal of Serbian despot Stefan Lazarević appointed to position of Lord of Mat and Kastoria before he died in 1390. Some authors, including Du Cange and Philippe Labbe, emphasized that Konstantin Kastrioti had additional surname - Mazarek (Latin: Meserechus). Jakob Philipp Fallmerayer referred to his second surname as Serbian.

According to Venetian document discovered by Karl Hopf his title was Lord of Cerüja castle (Latin: dominus Serinae). Hopf referred to Konstantin Kastrioti as protovestiar of Sina (Serina) near Durrazo.