The sixth edition of the WHO Manual for the Laboratory Examination and Processing of Human Semen is a reference document for procedures and methods for the laboratory examination and processing of human semen, which are intended to maintain and sustain the quality of analysis and the comparability of results from different laboratories. Semen analysis may be useful in both clinical and research settings, for investigating male fertility status as well as monitoring spermatogenesis during and following male fertility regulation and other interventions. This manual provides updated, standardized, evidence-based procedures and recommendations for laboratory managers, scientists and technicians to follow in examining human semen in a clinical or research setting. Detailed protocols for routine, optional and research tests are elaborated. The manual will benefit programmes that seek to improve sexual and reproductive health, including fertility care and access, especially among males, thereby supporting countries’ efforts to attain SDG 3.7 (universal access to sexual and reproductive health care services, including for family planning). The manual will also support accomplishment of SDG 3.8 (universal health coverage, including financial risk protection, and access to quality essential health care services).