Pyotr Nikolaevich Lebedev (Russian: Пётр Николаевич Лебедев) was a prominent Russian physicist.

He obtained his doctoral degree in Strasbourg under the supervision of August Kundt during 1887–1891. In 1891 he started working in Moscow State University  in the group of Alexander Stoletov. There he made his famous experimental studies of electromagnetic waves. He was the first to measure the pressure of light on a solid body in 1899. The discovery was announced at the World Physics Congress in Paris in 1900, and became the first quantitative confirmation of Maxwell's theory of electromagnetism. In 1901 he became a professor at Moscow State University, however he quit the University in 1911, protesting against the politics of the Ministry of Education. In the same year he received an invitation to become a professor in Stockholm, which he declined. He died the next year.

The Lebedev Physical Institute in Moscow and the lunar crater Lebedev are named after him.