Owing to the strong three-dimensional quantum-confinement effect of semiconductor quantum dots (QDs), QD lasers exhibit superior performances with low threshold current, high modulation rate, high temperature stability, low linewidth enhancement factor, and high antireflection. They are expected to have important applications in high-speed optical communication, high-speed optical interconnection, and other fields. At the same time, a QD structure is insensitive to dislocations, making QD lasers powerful candidates for the efficient light sources that are urgently needed for silicon optical integration. First, we briefly review the research progress on 1.3-μm semiconductor QD lasers, and then focus on the excellent characteristics exhibited by GaAs-based QD lasers, including their threshold current density, temperature stability, modulation rate, and antireflection characteristics. We also introduce QD lasers grown directly on GaAs and Si (001) substrates.