Silicon photonics has been intensively studied for future optical interconnects, telecom, datacom, and various sensor applications. While many high-performance passive components, such as waveguides, resonators, and detectors have been demonstrated, efficient and reliable light sources monolithically integrated on silicon remain challenging. III/V quantum dot (QD) lasers were initially studied for telecom applications due to their unique properties that can potentially enable very low threshold, temperature-insensitive, low reflection-sensitive and ultra-small foot-print lasers. Recently, we have witnessed that InAs/GaAs QD lasers can be grown on silicon by epitaxy while maintaining their superior performance. Advantages of QD over quantum well lasers on silicon are a longer lifetime, lower reflection sensitivity and smaller linewidth enhancement factor. Here, we present recent achievements in performance and reliability of the QD lasers epitaxially grown on silicon. Fabry-Perot QD lasers show a CW threshold current of 4.8 mA, linewidth enhancement factor of 0.1, extrapolated laser lifetimes of more than 10 million hours at 35 °C, and direct modulation up to 12 Gbps. We also show ultra-small microring QD lasers with a CW threshold of 0.5 mA and single-section mode-locked lasers with a 490 fs pulse width and 31 GHz repetition rate.