Yermak, Ermak or Jermak (Russian: Ермак; Ukrainian: Єрмак) is both a given name and a surname. Notable people with the name include:
Yermak Timofeyevich (born between 1532–1542), Russian explorer and conqueror of Siberia
Andriy Yermak (born 1971), Ukrainian lawyer, film producer and politician
Bronislav Yermak (born 1970), Russian businessman, banker and pilot. Died in a plane crash while piloting a Yakovlev Yak-52 in 2009
Dmitry Jermak (born 1983), Russian actor
Gennady Ermak (born 1963), Soviet-born scientist and writer
Lolita Yermak (born 1996), Ukrainian ice dancer
Maksim Yermak (born 1976), Russian and Ukrainian footballer
Oleh Yermak (born 1986), Ukrainian footballer
Pavel Jermak (born 1911), Soviet hero of WWII
Roman Jermak (born 2004), Kazakh Hockey Player
Stanislav Jermak (born 1939), Russian military man and rocket and space systems scientist
Vladimir Jermak (born 1924), Soviet hero of WWII