Poncirin, a flavanone glycoside with bitter taste extracted from dried immature fruit of Poncirus trifoliate, exhibits multiple biological activities including anti‐tumor activity. Our study aimed to determine the effect and potential mechanism of poncirin on cisplatin resistance in osteosarcoma (OS) cells. CCK‐8, flow cytometry analysis, and caspase‐3/7 activity assays were used to evaluate cisplatin sensitivity. The expression changes of multidrug resistance 1 (MDR1), multidrug resistance‐associated protein (MRP1), breast cancer resistance protein (BCRP), and phosphatidylinositol 3 kinase (PI3K)/protein kinase B (Akt) pathway‐related proteins were detected by RT‐qPCR or western blot analyses. Results showed that poncirin exposure enhanced cisplatin sensitivity, promoted apoptosis, and increased caspase‐3/7 activity in cisplatin‐resistant OS cells. Poncirin decreased the expression levels of MDR1, MRP1, and BCRP, and inhibited the PI3K/Akt signaling in OS cells. Rescue experiments suggested that activation of the PI3K/Akt signaling by 740Y‐P abolished poncirin‐induced expression reduction of MDR1, MRP1, and BCRP, and attenuated the facilitative effects of poncirin on cisplatin sensitivity and apoptosis in cisplatin‐resistant OS cells. In summary, poncirin suppressed cisplatin resistance in cisplatin‐resistant OS cells by downregulating the expression of MDR1, MRP1, and BCRP through inhibiting the PI3K/Akt pathway.