Nikolay Petrovich Likhachyov (Russian: Николай Петрович Лихачёв), alternatively transliterated as Likhachev (12 April 1862 – 14 April 1936) was the first and foremost Russian sigillographer (that is, an expert on seals) who also contributed significantly to an array of auxiliary historical disciplines, including palaeography, epigraphy, diplomatics, genealogy, and numismatics. He was elected a member of the Academy of Sciences of the USSR in 1925 and was put in charge of the Archaeographic Commission in 1929.
A scion of an old noble family, Likhachev was born in Chistopol, a town in the Kazan Governorate. Among his paternal uncles, Ivan Likhachyov was an admiral and Andrey Likhachyov was an avid antiquarian whose collections formed the core of the Kazan City Museum.
Nikolay Likhachyov graduated from the Kazan University in 1884 and joined the staff of the Saint Petersburg Archaeological Institute in 1892. His early work shed light on the hierarchy of 16th-century Muscovite clerks, or diaks. His doctor's dissertation was on the subject of Muscovite pulp manufacture and paper mills.
In 1902-14 Likhachyov filled the office of Assistant Director of the Imperial Public Library in St. Peterbsurg. During these years he brought to light a wealth of medieval papers, as well as many valuable materials concerning coins, watermarks, and hierarchy of medieval Russia. Together with Prince Aleksey Lobanov-Rostovsky he founded (in 1897) the Russian Genealogical Society.