Pyotr Vasilyevich Nikolsky (1858 – 1940) was a Russian dermatologist from Usman.
He studied medicine at the University of Kiev, and from 1884 was an assistant to Mikhail Stukovenkov at the dermatology clinic in Kiev. In 1900, he became a professor at Warsaw, and later worked as a professor in Rostov.
He published articles in French as well as Russian on skin diseases and on the treatment of syphilis. He was the author of L'etat de la dermatologie et de la syphiligraphie en Russie jusqu'à 1884 (The state of dermatology and syphiligraphy in Russia up to 1884).
In 1896, he published an article on pemphigus, in which he described a dermatological condition involving a weakening relationship among the epidermal layers. This condition is now referred to as "Nikolsky's sign".