Simonavičius is the masculine form of a Lithuanian family name. Its feminine forms are: Simonavičienė (married woman or widow) and Simonavičiūtė (unmarried woman).
The surname may refer to:
Kazimieras Simonavičius (1600–1651), Polish-Lithuanian general of artillery Jaunius Simonavičius (born 1954), Lithuanian politician, viceminister