This paper addresses the issues associated with physics and technology of diode lasers based on self-organized quantum dots (QDs). Theoretically predicted advantages of a QD array as the active region of a semiconductor laser and basic principles of QD formation using self-organization phenomena are discussed. Special attention is paid to relationship between structural and electronic properties of QDs and laser characteristics. Recent achievements in controlling these parameters including the effects of vertical stacking, changing the matrix bandgap and the surface density of QDs are reviewed. The threshold and power characteristics of the state-of-the-art QD lasers are demonstrated.