Csillag is a Hungarian surname meaning "star". Notable people with the surname include:
Balázs Csillag (born 1979), Hungarian long-distance runner Dárius Csillag (born 1995), Hungarian footballer Endre Csillag (born 1957), Hungarian guitarist Krisztián Csillag (born 1975), Hungarian footballer Levente Csillag (born 1973), Hungarian hurdler Róza Csillag (1832–1892), Hungarian mezzo-soprano Teréz Csillag (1862–1925), Hungarian actress
See also Csillag's disease Csillag fortress — one of the tree fortresses defending Komárno — Komárom from the right bank of Danube — Monostor, Ingmand and Csillag fort (Danube bridgehead)