Background Interest in physical and mental health outcomes in caregivers of patients with dementia is increasing. However, there is limited data available on the prevalence of suicidal ideation, suicidal attempts, and suicide rates among caregivers of those with dementia. Therefore, we aimed to systematically review these outcomes to address this gap in the literature and thus provide information to inform future policy and intervention for the benefit of caregivers of dementia patients. Methods We searched several databases from inception to the 10th November 2021, for studies investigating suicidal ideation, suicidal attempts, and suicide rates of caregivers of patients with dementia. We report data regarding suicidal ideation as prevalence, with the 95% confidence intervals (CIs), applying a random-effect model; since less than three studies were available for suicide attempt and suicide, these data are reported descriptively. Results Among 194 articles, eight comprising 1,209 informal caregivers of people with dementia (mean age: 63.9 years, 74% females) were included. The prevalence of suicide ideation was 32.32% (95% CI: 16.01–48.64%; I2 = 98.5%, p < 0.0001). The prevalence of suicide ideation varied between studies from 4.69% to 77.78%. Two studies reported the rate of suicidal attempt in caregivers of patients with dementia, with the prevalence ranging from 5.9% to 16.1%. One study reported one in 17 caregivers of patients with dementia died by suicide. Conclusions The prevalence of suicide ideation is high, affecting several caregivers of patients with dementia. These findings suggest intervention and/or policy are urgently needed to address suicidal behavior in this at-risk population.