PURPOSE: Walking adaptability is essential for children to participate in daily life, but no objective measurement tools exist. We determined psychometric properties of the Walking Adaptability Ladder test for Kids (WAL-K) in 6-12 year old children. MATERIALS AND METHODS: In total, 122 typically developing (TD) children and 26 children with Developmental Coordination Disorder (DCD) completed the single and double run conditions of the WAL-K. Intra-rater, inter-rater and test-retest reliability were determined by ICCs and Smallest Detectable Change (SDC) in 53 TD children. Construct validity was determined by comparing WAL-K scores between 69 TD and all DCD children and correlating these scores with age and MABC-2 scores. RESULTS: ICCs for reliability varied between 0.76 and 0.99. Compared to the first test performance, WAL-K scores were lower (i.e., better) at retest. SDCs for test-retest reliability varied between 20.8 and 26.1% of the mean scores. WAL-K scores were significantly higher (i.e., worse) in DCD children compared to TD children ( < 0.001). Significant negative correlations were found with MABC-2 (-0.52 and -0.60) and age (-0.61 and -0.68). CONCLUSIONS: The WAL-K shows to be a valid, reliable and easy-to-use tool for measuring walking adaptability in children. Adding an extra practice trial may reduce the observed learning effect.Implications for rehabilitationWalking adaptability is an essential skill for children to participate in daily life, but no objective measurement tools are available.The Walking Adaptability Ladder test for Kids (WAL-K) is a new measurement tool for evaluating walking adaptability in children.The WAL-K shows to be a reliable and valid measurement tool for evaluating walking adaptability in 6-12 year old children.