This review paper presents the fundamental principles related to the operational principles of flow modulators associated with comprehensive two-dimensional gas chromatography (GC×GC), as well as the main designs of flow modulators that have marked their technological evolution. Flow modulators present a great potential for the development of comprehensive two-dimensional gas chromatography, due to their low operational cost, which may turn GC×GC into a more accessible technique. In addition, it is possible to minimize the lack of sensitivity of a chromatographic system hyphenated to a mass spectrometric detector, with the use of low flow modulators (< 8 mL min–1).