BACKGROUND:Appropriate selection of robust assessment tools is essential to monitor physical function in children with cancer during and after treatment. This systematic review aims to identify and critically appraise the measurement properties of physical function measures currently used for children with cancer. PROCEDURE:Two systematic searches of seven electronic databases [Cumulative Index to Nursing and Allied Health Literature (CINHAL), Medline, PubMed, PsychINFO, Sportsdiscus, EMBASE, and Allied and Complementary Medicine Database (AMED)] were completed to identify physical function measures used in children with cancer and to evaluate their measurement properties. Methodological quality and the adequacy of measurement properties specific to populations of children with cancer were critically appraised using the COSMIN framework to ascertain which measures have evidence to support their use in children with cancer. RESULTS:One hundred and one physical function measures were identified across 154 studies. Measurement property data were available for 12 measures. The measurement properties of only two outcome measures were assessed in more than one study. Despite some positive measurement property data, there was no assessment tool that had consistent and adequate evidence overall to recommend its use in childhood cancer populations. Poor methodological quality of the included studies was the main limiting factor. CONCLUSIONS:There is very limited population specific evidence to guide the selection of physical function measures in children with cancer. Further research into the reliability, validity and responsiveness of physical function measures in children with cancer is needed to provide a basis for more effective clinical assessment and management.