Introduction: Acne vulgaris is more common in females than males and is challenging to treat. A post hoc analysis of 2 clinical trials evaluated the effect of dapsone gel, 7.5% based on sex and baseline acne lesion count. Methods: Two identically designed, randomized, double-blind, vehicle-controlled, multicenter, 12-week, phase 3 trials enrolled patients aged ≥12 years with facial acne and 20 to 50 inflammatory and 30 to 100 comedonal lesions. Patients applied dapsone gel, 7.5% or vehicle topically once daily for 12 weeks. Baseline to week 12 reductions were evaluated for total, inflammatory, and comedonal lesions in the pooled dapsone population by sex and total baseline acne lesion count (low: 50–74, medium: 75–99, and high: ≥100). Results: The analysis included 2160 patients (56% female, 44% male). Males and females had similar average baseline total, inflammatory, and comedonal lesion counts. Low, medium, and high subgroups experienced efficacy with dapsone gel, 7.5%. Females in each subgroup experienced superior efficacy to males. In females, total lesion counts in the low, medium, and high subgroups decreased by 56.07%, 50.22%, and 47.63%, respectively, compared with 47.95%, 42.30%, and 34.68% in males (P<0.001 for each male-female comparison). Females’ respective inflammatory lesion count percentage reductions were 60.96%, 57.91%, and 55.83%, versus 52.75% (P<0.001), 46.85% (P<0.001), and 44.70% (P=0.008) in males. Females’ respective comedonal lesion count percentage reductions were 52.96%, 45.40%, and 44.22%, versus 44.67% (P<0.001), 39.38% (P=0.030), and 29.89% (P=0.001) in males. The TEAE rate was low for the overall population (18.3%) and similar for females (19.0%) and males (17.4%). Males and females had similarly favorable dermal tolerability. Conclusion: Once-daily dapsone gel, 7.5% was efficacious for acne regardless of baseline total lesion count, with superior efficacy in females and similar tolerability in males and females. Registration identifier: Clinicaltrials.gov: NCT01974141 and NCT01974323