This paper discusses the self-assembled growth of In(Ga)As/GaAs quantum dots by metal-organic chemical vapor deposition and their application to diode lasers and integrated opto-electronic devices. After an extensive study of the growth parameters high densities (3-4×1010cm-2) of defect free quantum dots have been achieved and ground state lasing demonstrated for diode lasers with 5 stacked layers of quantum dots in the active region. This presentation will review the important growth parameters and the lasing characteristics of quantum dot lasers. Results for selective area epitaxy of quantum dots using SiO2 patterning will also be presented. Selective area epitaxy has been used to form quantum dots with different wavelength/bandgap in different regions of a GaAs substrate and has led to the integration of a quantum dot laser and waveguide.