Peroxisomes are single membrane organelles essential for human health. Peroxisomes are involved in key metabolic pathways including fatty acid β-oxidation, ether lipid synthesis, bile acid synthesis, cholesterol transport, and reactive oxygen species (ROS) metabolism. Beyond their metabolic roles, peroxisomes have emerged as important players in antiviral signaling, immune responses, and cellular stress responses, highlighting their broader significance in cellular homeostasis and human health. Mutations in PEX genes reduce peroxisome number or function, causing lethal peroxisome biogenesis disorders (PBDs), and altered peroxisome abundance is also observed in cancer and neurodegenerative disorders. The biogenesis of peroxisomes is a complex, dynamic process involving membrane formation, post-translational protein import, and maturation. In all these processes, ubiquitination plays an important role. We investigate the roles of several peroxisome-localized ubiquitin ligases to elucidate the molecular mechanisms underlying peroxisome biogenesis and degradation. Our research focuses on characterizing the enzymatic activity, substrate specificity and subcellular localization patterns of these ligases, aiming to provide comprehensive insights into how post-translational modifications orchestrate the dynamic processes of peroxisome assembly and function.