Objective: Ovary-on-a-chip platforms can simulate physiologic ovarian function in vitro. The ovarian follicle is the functional unit of an ovary which secretes reproductive hormones. The aim of this study was to develop a dynamic microfluidic ovary-on-a-chip platform comprising of multilayered engineered follicles that could demonstrate ovarian endocrine function in vitro and implant it in an ovariectomized rat to reestablish hormonal function in vivo. Methods: Two types of engineered follicles - bi-layered with inner granulosa cells surrounded by outer theca cells (BF), and tri-layered with a 5% matrigel basal membrane between the two cell layers (TF) - were crafted through forced aggregation of cells isolated from 3-5 week old rats. Dynamic microfluidics was constructed in a 3D network of thermo-responsive poly(N-isopropylacrylamide) microfibers. Hormone secretion of 17β-estradiol, progesterone, and testosterone were measured by ELISA in static and dynamic cultures. Ovariectomy was done to mimic surgically menopaused status and TF ovarian chips were implanted in the ischemic region of the hind limb. Hormone secretion was measured in control, ovariectomy only, ovarian chip implant after ovariectomy, and exogenous estrogen administration after ovariectomy groups. Results: Spheroid circularity was maintained in all engineered follicles, except the dynamic BF spheroid. Cell viability was maintained for both dynamic BF and TF spheroids, while both static BF and TF spheroids had decreased cell viability (<60%) on day 30. Hormonal production was highest in dynamic TF spheroids, which were found to be the optimal ovary-on-a-chip platform to demonstrate hormone secretion in vitro. Successful menopause status was confirmed after ovariectomy. Hormonal secretion levels of 17β-estradiol in ovariectomized rats implanted with TF ovarian chips were comparable to both the control and exogenous estrogen administration group on post-op day 13 and onwards. Conclusion: The microfluidic ovary-on-a-chip platform using engineered follicles with a matrigel basal membrane yielded the best hormone secretion results in vitro. Ovarian endocrine function was restored after implanting this platform chip in ovariectomized rats, establishing an operational ovary-on-a-chip model for future physiology research.