Peroxisomes are dynamic and metabolically plastic organelles. Their multiplicity of functions impacts on many aspects of plant development and survival. New functions for plant peroxisomes such as in the synthesis of biotin, ubiquinone and phylloquinone are being uncovered and their role in generating reactive oxygen species (ROS) and reactive nitrogen species (RNS) as signalling hubs in defence and development is becoming appreciated. Understanding of the biogenesis of peroxisomes, mechanisms of import and turnover of their protein complement, and the wholesale destruction of the organelle by specific autophagic processes is giving new insight into the ways that plants can adjust peroxisome function in response to changing needs.