Recent studies have shown that preferences for close relationships (Long-Term Relationship Orientation) are independent of preferences for various sexual partners (Short-Term Relationship Orientation). In the current studies, we hypothesized that Short-Term Relationship Orientation would be negatively related to 2D:4D finger-length ratio (i.e., the more masculine, the higher Short-Term Relationship Orientation). Study 1 found a negative relationship between Short-Term Relationship Orientation and right, but not left, hand 2D:4D among 91 male participants. Study 2 found a negative relationship between Short-Term Relationship Orientation and left, but not right, hand 2D:4D among 65 male participants, even after controlling for age, relationship status, social desirability, and sex drive. Female participants (n = 142) did not show this relationship in Study 2. This sex difference was discussed in terms of flexible female sexual strategies, which are supposed to be contingent on the local environment or menstrual cycle variations.