Objective: To review the efficacy and safety of niraparib for the treatment of recurrent epithelial ovarian, fallopian tube, and primary peritoneal cancer (OC, FTC, and PPC). Data Sources: A literature search via MEDLINE through PubMed from August 2013 to January 2020 was performed using the key terms niraparib, PARP inhibitors, ovarian cancer, fallopian tube cancer, and primary peritoneal cancer. Study Selection and Data Extraction: Completed and ongoing trials were identified through a review of the website trial registry https://www.clinicaltrials.gov . Data Synthesis: In a phase III, double-blind clinical trial, progression-free survival improved in patients treated with niraparib compared with placebo as maintenance treatment for patients with platinum-sensitive, recurrent OC: 21 versus 5.5 months in the germline breast cancer susceptibility gene ( gBRCA) cohort (hazard ratio [HR] = 0.27; 95% CI = 0.17 to 0.41; P < 0.001) and 9.3 versus 3.9 months in the overall nongermline breast cancer susceptibility gene (non- gBRCA) cohort (HR = 0.45; 95% CI = 0.34 to 0.61; P < 0.001). Adverse events included thrombocytopenia and anemia. Relevance to Patient Care and Clinical Practice: Poly (ADP-ribose) polymerase (PARP) inhibitors have gained a place in the therapeutic management of OC, FTC, and PPC because of their ability to suppress growth of homologous recombination deficiency–positive tumors, including those with BRCA1/2 mutations. Niraparib inhibits the DNA repair mechanism vital to the survival of cancer cells, poly-ADP ribose polymerase. Conclusions: PARP inhibitors can be used as a single agent for maintenance therapy for platinum-sensitive recurrent disease in patients with partial or complete response following 2 or more rounds of platinum-based therapy.