Uterine fibroids (leiomyomas) are common benign smooth muscle tumors that impose substantial symptom burden and healthcare costs worldwide. Although uterine fibroid (leiomyoma) pathogenesis is multifactorial, hypoxia has emerged as a key feature of the uterine fibroid (leiomyoma) microenvironment, particularly within poorly perfused tumor cores. Hypoxia-inducible factor-1α (HIF-1α) is a central transcriptional regulator of cellular adaptation to low oxygen and coordinates downstream programs that support angiogenesis, metabolic reprogramming, cell survival, and extracellular matrix (ECM) remodeling. In uterine fibroids (leiomyomas), these HIF-1α–dependent processes intersect with steroid hormone signaling, growth factor pathways, inflammatory mediators, and redox imbalance, together promoting tumor persistence and progressive fibrosis. This review synthesizes the molecular regulation of HIF-1α, highlights major HIF-linked effector pathways relevant to uterine fibroid (leiomyoma) biology, and emphasizes mechanistic crosstalk with estrogen- and progesterone-responsive signaling, TGF-β/SMAD-driven fibrosis, NF-κB-mediated inflammation, and metabolic checkpoint pathways including mTOR and AMPK. Finally, we evaluate emerging therapeutic strategies that target HIF-1α directly or indirectly through upstream regulators.