Objective To identify oncologists', nurses', and social workers' strategies and barriers in identifying suicide risk in cancer patients. Methods Sixty‐one oncology healthcare professionals (HCPs) at 2 cancer centers were interviewed. We used the grounded theory method (GT) of data collection and analysis. Analysis involved line‐by‐line coding, and was inductive, with codes and categories emerging from participants' narratives. Results The majority of oncologists and nurses reported that they had encountered at least 1 patient who had committed suicide during their careers (56% and 55%, respectively) and/or had suicidal ideation (65% and 75%, respectively). Social workers reported having fewer suicides in their practices (22%), but similar rates of suicidal ideation among patients (66%). Strategies to identifying suicide risk included paying attention to patients' verbal indicators, explicit actions, and mental health distress. In addition HCPs reported that mental health disorders and other patient characteristics increased their likelihood to assess suicidality among patients. Reported barriers to identification included patient factors such as patients giving no warning, patients concealing suicidality, and patients failing to come in. HCP barriers to identification included lack of training and awareness, difficulty in differentiating suicidality from mental health distress, lack of time with patients, fear of asking about suicidality, and lack of coping resources to deal with suicidal patients. Conclusions HCPs reports of their lack of training and awareness on identifying suicide risk is alarming given the higher risk of suicide among cancer patients. Training programs should incorporate the successful strategies used by HCPs and overcome barriers to identifying suicide risk.