Hoàng Tụy's early career coincided with the French war (1946–1954), which interrupted his studies. In December 1946, after two months as a mathematics student at Hanoi University, he had to return to the south, because the French had invaded and seized Hanoi, and the University had closed. Hoàng Tụy taught secondary school in Quảng Ngãi province in the Fifth Liberated Zone from 1947 to 1951, during which time he wrote a geometry textbook that was published by the Việt Minh press—perhaps the first time a guerrilla movement published a math book. In the early 1950s, Hoàng Tụy studied with Lê Văn Thiêm in the university that the Việt Minh had opened in a liberated zone in the far north near the Chinese border. In September 1957 he went to the Soviet Union, where he studied real analysis under the supervision of D. E. Menshov and G. E. Shilov. Hoàng Tụy received his PhD in mathematics from Moscow State University in 1959.