Slovakia competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. This was the nation's third consecutive appearance at the Summer Olympics since the post-Czechoslovak era. The Slovak Olympic Committee sent a total of 64 athletes to the Games, 48 men and 16 women, to compete in 11 sports. There was only a single competitor in artistic and trampoline gymnastics and sailing.

The Slovak team featured four Olympic medalists from Sydney: freestyle and butterfly swimmer Martina Moravcová, twins Pavol and Peter Hochschorner, and slalom canoeist Michal Martikán, who later became the nation's flag bearer in the opening ceremony. Along with Moravcova, sprint canoeist Peter Páleš and track cyclist Jaroslav Jeřábek were among the Slovak athletes to compete in four editions of the Summer Olympics, although they previously appeared as part of the Czechoslovak team (Pales in 1988; Jerabek and Moravcova in 1992). Other notable Slovak athletes featured professional tennis players Daniela Hantuchová and Karol Beck, rifle shooter and former Olympic medalist Jozef Gönci, and slalom kayak world champion Elena Kaliská.

Slovakia left Athens with a total of six Olympic medals, an equal allocation of gold, silver, and bronze with two each, surpassing a single short of the tally from Sydney four years earlier. While the Hochschorner twins defended their Olympic title in double slalom canoeing, Slovak athletes continued to dominate the sport, as Elena Kaliská and Michal Martikán managed to claim Olympic medals in their respective events. Jozef Gönci added a second bronze to his Olympic career in men's air rifle shooting, while Jozef Krnáč set a historic milestone for Slovakia, after earning the nation's first Olympic medal in judo.