Endometriosis is a chronic, estrogen-dependent inflammatory disorder that is increasingly recognized as a systemic condition with profound implications for female reproductive potential. In addition to pelvic distortion and impaired folliculogenesis, growing evidence indicates that intrinsic alterations in oocyte morphology, mitochondrial function, and developmental competence contribute to infertility. The disease is driven by a multifactorial interplay of somatic mutations, epigenetic remodeling, immune dysregulation, and aberrant steroid signaling, which together create a pro-inflammatory, oxidative, and fibrotic microenvironment. Elevated cytokines, reactive oxygen species, and disrupted granulosa-cell function within the follicular niche impair meiotic progression, cytoplasmic maturation, and mitochondrial integrity, potentially accelerating oocyte aging and diminishing reproductive longevity. Epigenetic and post-transcriptional disturbances—including altered DNA methylation, histone modifications, and RNA-splicing defects—further reinforce estrogen dominance, progesterone resistance, and impaired decidualization, with downstream consequences for ovarian–endometrial communication. Although morphological abnormalities have been documented in oocytes from women with endometriosis, clinical outcomes remain heterogeneous, highlighting the need for integrative models that connect molecular alterations to functional reproductive endpoints. A deeper understanding of these mechanisms is essential for identifying biomarkers of oocyte competence and modifiable strategies—ranging from nutritional optimization to reduction of environmental risk factors—in clinical care to safeguard the reproductive potential of women with endometriosis.