Lyapunov (, in old-Russian often written Лепунов) is a Russian surname that is sometimes also romanized as Ljapunov, Liapunov or Ljapunow. Notable people with the surname include:
Alexey Lyapunov (1911–1973), Russian mathematician Aleksandr Lyapunov (1857–1918), son of Mikhail (1820–1868), Russian mathematician and mechanician, after whom the following are named: Lyapunov dimension Lyapunov equation Lyapunov exponent Lyapunov function Lyapunov fractal Lyapunov stability Lyapunov's central limit theorem Lyapunov time Lyapunov vector Lyapunov (crater) Boris Lyapunov (1862–1943), son of Mikhail (1820–1868), Russian expert in Slavic studies Mikhail Lyapunov (1820–1868), Russian astronomer Mikhail Nikolaevich Lyapunov (1848–1909), Russian military officer and lawyer Prokopy Lyapunov (d. 1611), Russian statesman Sergei Lyapunov (1859–1924), son of Mikhail (1820–1868), Russian composer Zakhary Lyapunov (d. after 1612), Russian statesman, Prokopy Lyapunov's brother
See also Lyapunov family, a Russian noble family, to which not all the above individuals necessarily belong