Dyslexia is one of the most frequent disorders of childhood and adolescence with an incidence of 4–7%. Prerequisites for diagnosis are performance of a general intelligence test and a test to measure specific orthographic and reading abilities. The scores in the reading and/or writing test must be below a percent rank of 10–16. In addition, a discrepancy between intelligence quotient and percent rank in the reading and/or writing test of at least 1.5–2 SD is necessary for the diagnosis. To classify the clinical picture, comprehensive diagnostic tests must also be performed according to the multiaxial system for child and adolescent psychiatry or multidimensional diagnostic work-up of social pediatrics. If the tests reveal secondary or concomitant disorders, these must be integrated into the treatment plan. Many cases require comprehensive therapeutic cooperation between patient, family, school, institution, physicians, and therapists.