Roman Ivanovich Klein (Russian: Роман Иванович Клейн), born Robert Julius Klein, was a Russian architect and educator, best known for his Neoclassical Pushkin Museum in Moscow. Klein, an eclectic, was one of the most prolific architects of his period, second only to Fyodor Schechtel. In the 1880s-1890s, he practiced Russian Revival and Neo-Gothic exteriors; in the 1900s, his knowledge of Roman and Byzantine classical architecture allowed him to integrate into the Neoclassical revival trend of that period.