Konstantin Adolfovich Semendyayev (Russian: Константин Адольфович Семендяев; 9 December 1908, Simferopol – 15 November 1988, Moscow) was a Soviet engineer and applied mathematician.

Semendyayev is known as the co-author of a handbook of mathematics for engineers and students of technical universities,[1] which he wrote together with Ilya Nikolaevich Bronshtein around the 1939/1940 timeframe.

Hot lead typesetting for the work had already started when the Siege of Leningrad prohibited further development and the print matrices were relocated.

[1] After the war, they were first considered lost, but could be found again years later, so that the first edition of Справочник по математике для инженеров и учащихся втузов could finally be published in 1945.

[1][2] However, in a parallel development starting in 1970, the so called "Bronshtein and Semendyayev" (BS), which had been translated into German in 1958, underwent a major overhaul by a team of East German authors around Günter Grosche, Viktor & Dorothea Ziegler (of University of Leipzig), to which Semendyayev contributed as well (a section on computer systems and numerical harmonic analysis).