The paper discusses the use of internal second‐harmonic generation as a means of lengthening the pulses of Q‐switched lasers. The second‐harmonic generator acts as both a nonlinear power‐dependent loss and as an output coupler for the laser. The lengthening arises if the coupling to the second harmonic is greater than that necessary to maximize the peak second‐harmonic power. It is shown that a pulse‐lengthening factor of about 100 should be obtainable.