Chlamydia pneumoniae and Chlamydia trachomatis are significant human pathogens that affect people of all ages worldwide. Chlamydia psittaci is a cause of zoonosis, and birds are the reservoirs. All are diseases for which there is no effective vaccine. C. pneumoniae is responsible for respiratory tract infections but the majority of recent C. pneumoniae research has focused on the persistent infections associated with chronic diseases and has been considered a childhood infection with potential adult consequences. C. trachomatis is one of the most common sexually transmitted diseases (STDs), and the prevalence of the infection is particularly high among young people and adolescents. Prepubertal infection of C. trachomatis may be a warning sign for probable child sexual abuse (CSA). In addition to its role in genital diseases, trachoma is one of the world’s leading preventable causes of blindness. C. trachomatis can also cause Lymphogranuloma venereum (LGV), a systemic, sexually transmitted disease characterized by genital ulceration and inguinal lymphadenopathy. This chapter aims to provide an overview of Chlamydia infections in childhood and summarize the epidemiology, clinical manifestations, and treatment.