Testicular cancer survivors may experience mental illness as a consequence of their cancer diagnosis and treatment.All incident cases of testicular cancer treated with orchiectomy in Ontario, Canada (2000-2010), were identified using the Ontario Cancer Registry. Cases were matched to controls in a 1:5 ratio on age and geography. Population-level databases were used to identify mental health service use episodes; outpatient use included visits to a general practitioner for a mental health concern or any visit to a psychiatrist. Negative binomial regression modeling was used to estimate the rate of mental health service use in the pretreatment (2 years prior until 1 month before orchiectomy), peritreatment (1 month before until 1 month after orchiectomy), and post-treatment periods (1 month after orchiectomy until end of follow-up). Rate ratios (RR) comparing cases with controls in the peri- and post-treatment periods were adjusted for baseline mental health service use.Two thousand six hundred nineteen cases of testicular cancer were matched to 13,095 controls. There was no baseline difference in the rate of mental health service use. Cases were significantly more likely than controls to have an outpatient visit for a mental health concern in the peritreatment (adjusted RR [aRR], 2.45; 95% CI, 2.06 to 2.92) and post-treatment periods (aRR, 1.30; 95% CI, 1.12 to 1.52). The difference in mental health service use persisted over a median follow-up of 12 years. In the postorchiectomy period, cases with baseline mental health service use were those most likely to use mental health services (aRR, 5.64; 95% CI, 4.64 to 6.85).Testicular cancer survivors use mental health services more often than healthy controls. Survivorship care plans that address the long-term mental healthcare needs of this population are needed.