The aim of this study was to investigate the convergent and divergent validity between the Body Coordination Test for Children (KTK) and the Motor Proficiency Test for 4- to 6-Year-Old Children (MOT 4-6). A total of 638 children (5–6 yr old) took part in the study. The results showed a moderately positive association between the total scores of both tests (r s = .63). Moreover, the KTK total score correlated more highly with the MOT 4-6 gross motor score than with the MOT 4-6 fine motor score (r s = .62 vs. .32). Levels of agreement were moderate when identifying children with moderate or severe motor problems and low at best when detecting children with higher motor-competence levels. This study provides evidence of convergent and divergent validity between the KTK and MOT 4-6. However, given the moderate to low levels of agreement, either measurement may lead to possible categorization errors. Therefore, it is recommended that children’s motor competence not be judged based on the result of a single test.