Arnajevo (Cyrillic: Арнајево) is a suburban settlement of Belgrade, the capital of Serbia. It is located in the municipality of Barajevo.
Arnajevo is located in the northwestern tip of the municipality, east of the village of Stepojevac. It is a small, depopulating rural settlement with a population of 853 according to Census 2002. In 1991, settlement had 1,005 inhabitants.
In 1956-57, Arnajevo was part of the municipality of Beljina, which in 1957 merged into the municipality of Barajevo.