Rybka is a computer chess engine designed by International Master Vasik Rajlich. As of February 2011^[update], Rybka is one of the top-rated engines on chess engine rating lists and has won many computer chess tournaments.

Although Rybka won four consecutive World Computer Chess Championships from 2007 to 2010, it was stripped of these titles after an International Computer Games Association panel concluded in June 2011 that Rybka plagiarized code from both the Crafty and the Fruit chess engines. Others dispute this.

The word rybka, pronounced [ˈrɪpka], means little fish in Czech (and in many other Slavic languages) and Vasik Rajlich was once asked in an interview by Alexander Schmidt, "Did you choose the name Rybka because your program always slipped out of your hands like a little fish?" He replied, "As for the name Rybka - I am sorry but this will remain my private secret." It is interesting to point out that the programmer's wife, Iweta Rajlich (Radziewicz), was born under an astrological sign of Pisces. Iweta Radziewicz was born in Poland and is still considered one of the strongest female chess players. The word rybka means exactly the same in the Polish and Czech languages. It is also known that Iweta was the main tester for the program.