Women with minority sexual orientations (e.g., lesbian, bisexual) are more likely than heterosexual women to report histories of childhood maltreatment and attempted suicide; however, the importance of the timing of minority sexual orientation development in contributing to this increased risk is uncertain. This study investigated relationships between self-reported ages of achieving minority sexual orientation development milestones (first awareness of same-gender attractions, disclosure of a minority sexual orientation to another person, and same-gender sexual contact), and childhood maltreatment and suicide attempt experiences in a sample of 2, 001 women recruited from multiple-community sources. Younger age of minority sexual orientation development milestones was positively linked to self-reported recall of childhood maltreatment experiences, and to a childhood suicide attempt. After adjusting for differences in maltreatment, the odds of suicide attempt attributable to younger age of sexual orientation development milestones was reduced by 50 to 65%, suggesting that maltreatment may account for about half of the elevated risk for childhood suicide attempts among women with early minority sexual orientation development. Implications for services, interventions, and further research to address maltreatment disparities for sexual minorities are discussed.