Instead of individual abilities or skills, at the beginning of the 21st century, learners are expected to develop competence. That is, individuals must be able to integrate a broad range of abilities and skills to meet the challenges of todays’ life. Measuring competence requires a model of competence, assessment tasks and statistical models that allow to infer an individual’s competence from his or her performance on the respective tasks. The chapter discusses types of competence models, the design of assessment tasks and the most common statistical models based on examples from competence research.