Introduction: Post-mastectomy breast reconstruction is crucial in breast cancer treatment; however, its impact on women’s quality of life (QOL) remains inadequately understood. The BREAST-Q questionnaire is used for assessing QOL related to breast surgery. Therefore, this study aimed to determine whether there are differences in QOL between women undergoing mastectomy with and without breast reconstruction using the BREAST-Q questionnaire. Methods: We conducted a systematic review and meta-analysis following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines and registered in PROSPERO. Articles in English, Portuguese, or Spanish were included, and studies on prophylactic mastectomy or breast-conserving surgery, duplicate studies, duplicate data, articles without original data (reviews, editorials, case reports, technical reports) and those without breast reconstruction were excluded. A comprehensive search was conducted across nine scientific databases. The defined search strategy was related to the terms standardized by the MeSH/PubMed controlled vocabularies, including Medical Subject Headings (MeSH), Embase subject headings (Emtree), and their synonyms. Statistical heterogeneity was assessed using the chi-squared and inconsistency tests. Statistical analyses were performed using the R software. A meta-analysis was performed for each BREAST-Q domain when data from multiple studies were available. Results: Of 1266 studies identified, three with 611 participants were included in the meta-analysis. Of these participants, 248 underwent mastectomy without reconstruction and 363 underwent post-mastectomy breast reconstruction. The meta-analysis revealed significantly higher scores in the domains “satisfaction with the breast,” “physical well-being of the chest,” “psychosocial well-being,” and “physical well-being” in women who underwent breast reconstruction compared with those who did not. Conclusion: This study demonstrates a positive association between breast reconstruction and enhanced QOL in women undergoing breast cancer treatment and mastectomy. Patient-reported outcome measures using questionnaires, such as Breast-Q, can elucidate satisfaction levels with the reconstruction, which will likely improve continuously with advances in modern plastic surgery.