Oral contraceptives (OCs) provide safe, effective, and reversible contraception and are widely used by women for fertility control. Little is known about the effects of OCs on sexual functioning. This paper critically examines the published literature addressing the impact of OCs on sexual desire or libido. We reviewed 30 original research studies. In the retrospective, uncontrolled studies (n = 17), it was found that most women reported an increase in libido during OC use. In the uncontrolled, prospective studies (n = 4), it was found that most women reported little change in libido during OC use. In the prospective and cross-sectional controlled studies (n = 4), women using OCs reported both increased and decreased libido compared to non-OC users. The findings from randomized, placebo-controlled studies (n = 5) were mixed: In the most recent and well-conducted trial, a decrease in libido in OC users compared to placebo users was found. Overall, women experience positive effects, negative effects, as well as no effect on libido during OC use. Better-designed studies are needed to establish the independent, causal effects of OCs on libido.