Lipid metabolism plays an important role in the occurrence and development of cancer, in particular, digestive system tumors such as colon cancer. Here, we investigated the role of the fatty acid-binding protein 5 (FABP5) in colorectal cancer (CRC). We observed marked down-regulation ofFABP5in CRC. Data from functional assays revealed inhibitory effects ofFABP5on cell proliferation, colony formation, migration, invasion as well as tumor growthin vivo. In terms of mechanistic insights,FABP5interacted with fatty acid synthase (FASN) and activated the ubiquitin proteasome pathway, leading to a decrease inFASNexpression and lipid accumulation, moreover, suppressingmTORsignaling and facilitating cell autophagy. Orlistat, aFASNinhibitor, exerted anti-cancer effects bothin vivoandin vitro. Furthermore, the upstream RNA demethylaseALKBH5positively regulatedFABP5expression via an m6A-independent mechanism. Overall, our collective findings offer valuable insights into the critical role of theALKBH5/FABP5/FASN/mTORaxis in tumor progression and uncover a potential mechanism linking lipid metabolism to development of CRC, providing novel therapeutic targets for future interventions.