Polycystic ovary syndrome (PCOS) is the most prevalent endocrine-metabolic disorder in women of reproductive age, and is characterized by hyperandrogenism, anovulation, and polycystic ovarian morphology. Emerging molecular evidence has identified dysregulated ovarian steroidogenesis as a major contributing mechanism linking reproductive and metabolic phenotypes in PCOS, acting in concert with neuroendocrine and metabolic dysfunction. This review synthesizes current knowledge on enzymatic and regulatory perturbations driving androgen excess and estrogen deficiency in PCOS, emphasizing their mechanistic, diagnostic, and therapeutic implications. Dysregulated steroidogenic enzymes and associated signaling pathways contribute to androgen excess, impaired folliculogenesis, and metabolic dysfunction in PCOS. Importantly, these steroidogenic alterations are not uniform across all patients with PCOS but vary according to hyperandrogenic, anovulatory, ovulatory, lean, obese, reproductive, and metabolic phenotypes. Particular focus is placed on how these molecular derangements disrupt theca-granulosa cell communication, impair folliculogenesis, and promote hyperandrogenism, oxidative stress, and insulin resistance in the ovaries. This review also discusses therapeutic strategies according to evidence level, distinguishing established PCOS treatments such as lifestyle intervention, insulin sensitizers, ovulation-induction agents, hormonal regulators, and anti-androgens from investigational enzyme-specific inhibitors and speculative precision approaches such as gene editing and exosome-based delivery systems. Collectively, these insights underscore that the pathophysiology of PCOS extends beyond endocrine imbalance to encompass multi-omic alterations in metabolism and signaling. Understanding enzyme-level dysregulation offers opportunities for mechanism-based interventions that can restore steroidogenic homeostasis, improve fertility outcomes, and mitigate long-term metabolic r