BACKGROUND: Females aged ≥25 years may have acne with different etiology, presentation, burden, and treatment response than females 18–24 years. This post hoc analysis investigated efficacy and safety of tazarotene 0.045% lotion in females ≥18 years or ≥25 years of age. METHODS: In two phase 3 double-blind studies, participants 9 years of age and older with moderate-to-severe acne were randomized (1:1) to once-daily tazarotene 0.045% lotion or vehicle lotion for 12 weeks. Pooled data were analyzed for females aged ≥18 years (n=744) or ≥25 years (n=335). Assessments included inflammatory/noninflammatory lesion counts, treatment success (≥2-grade reduction from baseline in Evaluator’s Global Severity Score and score of 0 [clear] or 1 [almost clear]), Acne-Specific Quality of Life (Acne-QoL) questionnaire, treatment-emergent adverse events (TEAEs) and cutaneous safety/tolerability. RESULTS: At week 12, tazarotene-treated females in both age groups had greater reductions from baseline versus vehicle in inflammatory (≥18 years: 60.6% vs 53.7% [P<0.01]; ≥25 years: 60.9% vs 57.3% [P>0.05]) and noninflammatory lesions (59.0% vs 48.4% and 61.1% vs 48.8%; P<0.01, both). Rates of treatment success were greater with tazarotene versus vehicle; this difference was significant for females ≥18 years. Acne-QoL improvements were similar across age groups and generally greater with tazarotene than vehicle. TEAEs were mostly mild to moderate in severity. No age-related trends for safety or tolerability were observed. CONCLUSIONS: Tazarotene 0.045% lotion demonstrated comparable efficacy, improvement in quality of life, and safety in adult females aged ≥18 or ≥25 years with moderate-to-severe acne. This cosmetically elegant lotion is a well-studied and important treatment option for all patients, particularly adult females. J Drugs Dermatol. 2022;21(5):587-595. doi:10.36849/JDD.6876.