Postnik Yakovlev (Постник Яковлев), nicknamed "Barma" (Барма) ('the mumbler'), was the architect of St. Basil's Cathedral in Moscow.

According to legend, Ivan the Terrible blinded him so that he could never build anything so beautiful again. However, this is probably a myth, as Postnik designed the northeast chapel of St. Basil's years later, in 1588.

According to some historians, Barma was Yakovlev's assistant.