This paper examines the technological evolution, application, and cost trend of photovoltaic (PV) technology over the last three decades. It presents the longest experience curve for PV systems assembled to date; stretching back to the pre-commercialization period in the late 1960s. Cooperative investments by manufacturers and individual governments have resulted in the accumulation of experience within the solar industry and the subsequent cost reduction of PV systems. Significant cost reductions have occurred in both PV modules, that house the solar cells, and the ancillary components, known as balance-of-system (BOS). Between 1968 and 1998, the worldwide cumulative installed capacity of PV modules doubled more than thirteen times, from 95 kW to 950MW, while costs ($/Wp) were reduced by an average of 20.2% for each doubling. Cost reductions for PV modules are attributed to technology innovation, manufacturing improvements, and economies of scale. Though BOS are difficult to compare to one another - due to the customization of PV applications - targeted studies have shown that BOS costs have fallen over the past two decades and in some instances, more than module costs. BOS cost reductions are attributed to greater system integration and the experience  of system designers and installers. Future cost improvements will be attained through greater standardization and pre-assembly of BOS components in the factory.