The aim of the study is to evaluate the effect of high-intensity focused ultrasound (HIFU) treatment on ovarian reserve by synthesizing available evidence on post-treatment changes in ovarian reserve markers. Studies were eligible if they evaluated the impact of HIFU on ovarian reserve by reporting pre- and post-treatment ovarian reserve markers, including anti-Müllerian hormone (AMH), antral follicle count (AFC), or gonadotropin levels. MEDLINE, Scopus, and CENTRAL were searched from inception to January 5, 2026. Two reviewers independently screened titles and abstracts, assessed full texts, and evaluated risk of bias using the Cochrane Risk-of-Bias tool for randomized trials or the JBI critical appraisal tool for case series. Disagreements were resolved through discussion or consultation with a third reviewer. Of 2498 records identified, 1935 were screened after removal of duplicates, 24 articles underwent full-text review, and 10 studies were included in the systematic review and single-arm meta-analysis. This review included 2 randomized controlled trials and 8 case series (n = 667). The duration of follow-up after HIFU ranged between 3 and 24 months. Overall pooled analysis of all studies showed a small but statistically significant reduction in serum AMH levels (MD = -0.12 ng/mL; 95% CI = -0.20 to -0.04, I[2] = 0%). Pooled analysis of AFC (2 studies, n = 140) revealed no statistically significant change after HIFU treatment (MD = -0.05; 95% CI = -0.28 to 0.19; I[2] = 0%). The reduction in AMH persisted when the analysis was restricted to fibroid-only studies (MD = -0.13 ng/mL; 95% CI = -0.22 to -0.05), whereas data were insufficient for an adenomyosis-specific estimate. Pooled single-arm analysis showed a small but statistically significant reduction in serum AMH levels following HIFU treatment, with no significant change in AFC. This decline was associated with, rather than proven to be caused by, HIFU treatment, as the available evidence derives predominantly from uncontrolled pre-post studies that cannot establish causality. Therefore, evaluation of ovarian reserve after HIFU should not rely on AMH alone but incorporate AFC and clinical context. Pre-treatment counseling is particularly important in women with diminished ovarian reserve or of late reproductive age, in whom even minor reductions may be clinically relevant.