Testicular cancer is cancer that develops in the testicles, a part of the male reproductive system.

In the United States, between 7,500 and 8,000 diagnoses of testicular cancer are made each year. In the UK, approximately 2,000 men are diagnosed each year, and over his lifetime, a man's risk of testicular cancer is roughly 1 in 200 (0.4%). It is the most common cancer in males aged 20–39 years, the period of peak incidence, and is rarely seen before the age of 15 years.