Participants
Girls were recruited across the USA. Eligible participants were (1) aged 14 to 18 years, (2) cisgender (i.e., assigned female sex at birth and endorsed a female gender identity), (3) sexual minority (i.e., had a sexual identity other than heterosexual), (4) had not yet graduated high school, (5) English speaking, (6) owned their own cell phone and had an unlimited text messaging plan, (7) intended to have the same cell phone number for 12 months, (8) had used text messaging for at least 6 months, and (9) were able to provide informed assent for those under 18 years of age and informed consent for those 18 years of age, including the capacity to assent/consent and to pass a self-safety assessment. Those who knew another girl in the RCT or had participated in an intervention development activity (e.g., focus groups) were excluded.