Previous research has found that single heterosexual (Het) men have higher salivary testosterone (T) concentrations than partnered Het men. Here, we used both longitudinal and cross-sectional analyses to examine a more diverse population (n = 258) that included Het and non-heterosexual (Non-Het) women and men. Results showed that, for Het men (but not Het women) and Non-Het women (but not Non-Het men), baseline T was significantly lower in partnered than unpartnered individuals. Longitudinal analyses indicated that changes in partnered status were not associated with changes in testosterone concentrations; instead, women and men with lower T at baseline were significantly more likely to be partnered at follow-up. These findings thus suggest that partnered status is associated with stable, trait-level T values, rather than current state. Furthermore, the observed effect is limited to individuals (male or female) who are oriented toward female partners. The results are discussed in terms of evolutionary trade-offs between single and multiple partners, and the possibility of female choice and/or disinterest.