Background Gatekeeper training aims to train people to recognize and identify those who are at risk for suicide and assist them in getting care. Applied Suicide Intervention Skills Training (ASIST), a form of gatekeeper training, has been implemented around the world without a controlled evaluation. We hypothesized that participants in 2 days of ASIST gatekeeper training would have increased knowledge and preparedness to help people with suicidal ideation in comparison to participants who received a 2‐day Resilience Retreat that did not focus on suicide awareness and intervention skills (control condition). Methods First Nations on reserve people in Northwestern Manitoba, aged 16 years and older, were recruited and randomized to two arms of the study. Self‐reported measures were collected at three time points—immediately pre‐, immediately post‐, and 6 months post intervention. The primary outcome was the Suicide Intervention Response Inventory, a validated scale that assesses the capacity for individuals to intervene with suicidal behavior. Secondary outcomes included self‐reported preparedness measures and gatekeeper behaviors. Results In comparison with the Resilience Retreat (n = 24), ASIST training (n = 31) was not associated with a significant impact on all outcomes of the study based on intention‐to‐treat analysis. There was a trend toward an increase in suicidal ideation among those who participated in the ASIST in comparison to those who were in the Resilience Retreat. Conclusions The lack of efficacy of ASIST in a First Nations on‐reserve sample is concerning in the context of widespread policies in Canada on the use of gatekeeper training in suicide prevention.