Beloiannisz (in Greek: Μπελογιάννης) is a village in Fejér county, Hungary. It was founded by Communist Greek refugees who left Greece after the civil war and was named after Nikos Beloyiannis (Beloiannisz is the Hungarian spelling of his name).
Beloiannisz is close to the railway station of Iváncsa, which is on the Budapest–Pusztaszabolcs railway line. On paved road the village can be reached through a 1 km long access road which links the village to the Iváncsa–Besnyő road. Most of the buses connecting Besnyő and Dunaújváros stop at the village, but railway plays a more important role.
The village is one of the youngest ones in the county, its design and construction started on May 6, 1950. The village was built in voluntary service, within a short time 418 houses, a school, a kindergarten, a library, a community hall, a doctor's office and a town hall were built. On April 3, 1952 the village (previously called Görögfalva, "Greek Village") took the name of Nikos Beloyiannis, the Communist leader and resistance fighter. The village had 1850 inhabitants then.
From 1954 several Greeks left the village and went back to Greece, but many of them (especially the younger people) stayed in Hungary. Now the majority of the population works in the nearby cities Százhalombatta and Dunaújváros. Lots of people are still keeping their Greek identity. At the latest census (2001) 23,4% of the population considered themselves Greek, 81,4% considered themselves to be Hungarians (which means lots of them feel themselves both Greek and Hungarian), 0,3% were Romanians and 15,9% didn't answer.
A Greek Orthodox church was built in 1996.