In this review article, the current status of quantum dot infrared photodetectors (QDIPs) compared to competitive infrared (IR) technologies will be evaluated. Carrier generation and some of the other important physical properties of quantum dots (QDs) will be discussed. Recent design improvements of epitaxial and colloidal QDIPs are presented, followed by a thorough discussion on the growth techniques for both types of QDs. Important figures of merit for QDIPs, including dark current, responsivity, detectivity, and noise equivalent differential temperature (NEDT), will be explained, and a comparison will be made between QDIPs performance and other IR technologies in terms of their figures of merit.