Relaxation oscillation frequencies are reported for short cavity GaAs/AlGaAs multiquantum well lasers with dry‐etched facets. Decreased electron and photon lifetimes combined with the high differential gain constant of short cavity lasers yield very high relaxation oscillation frequencies. A peak value of 24 GHz was achieved with a 40‐&mgr;m‐long laser, and a linear relationship between frequency and the square root of the output power is observed.