<p>Women with autoimmune rheumatic diseases (ARDs) face increased risks of infertility, yet fertility-related knowledge among physicians remains underexplored. We aimed to evaluate fertility and infertility knowledge among physicians treating women with rheumatic diseases, using the validated Fertility and Infertility Treatment Knowledge Score (FIT-KS). A cross-sectional web-based study was conducted among 102 physicians across different specialties in Mexico involved in the care of women with ARDs. Participants completed the FIT-KS, a 29-item questionnaire that assesses knowledge of natural fertility and infertility treatments. Recruitment occurred online between March and June 2025. Associations between participant characteristics and knowledge scores were analyzed. The mean FIT-KS score was 18.51 out of 29 (63.82%). Participants demonstrated good knowledge of basic fertility concepts (e.g., most fertile age, timing of conception). Still, notable gaps were observed in age-related fertility decline, IVF success rates, and treatment outcomes. Physicians under age 35 (95% CI 0.208–2.565) and females scored significantly higher (95% CI 0.646–2.99). Obstetrics and gynecology specialists had the highest scores (mean 19.87), while rheumatologists and internal medicine specialists scored lower (mean 17.95 and 17.85 (95% CI 0.24–3.80)). Fertility knowledge among physicians caring for women with ARDs is suboptimal, especially among non-reproductive specialists. To address these gaps, targeted education needs to be implemented through the integration of fertility and reproductive health topics into rheumatology fellowship curricula, offering continuing medical education sessions focused on fertility preservation and pregnancy planning, and conducting interdisciplinary workshops. These initiatives should aim to enhance knowledge, confidence, and communication in fertility counseling.</p>