Background: Suicide is a major public health problem, and most people, who attempt suicide, have a psychiatric disorder. The preventable nature of suicide has further warranted the conduct of studies on suicide. Methods: This cross-sectional and descriptive study aimed to investigate the effects of depression, anxiety, and stress levels on suicidal behavior in patients with schizophrenia. The study included 222 patients with schizophrenia. Data were collected by using the Descriptive Information Form, the Suicide Behaviors Questionnaire, and the Depression Anxiety Stress Scales—Short Form. Results: It was found that 47.7% of the participants had suicidal ideation and 33.8% of them had attempted suicide by taking pills, self-cutting, jumping from a height, and hanging. While the participants had moderate levels of depression and anxiety, their stress levels were normal. The study has shown that the variables of stress, a good income level, and employment affect suicidal behavior, with a 1-unit increase in stress scores leading to an increase by 0.942, a 1-unit decrease in the good income level leading to an increase by 1.132, and a 1-unit increase in employment leading to an increase by 1.316 in suicidal behavior. Stress, income status, and employment accounted for 42.3% of the change in suicidal behavior. Conclusion: This study has shown that suicidal ideation and suicide attempts are common in patients with schizophrenia compared to the normal population, and increased stress levels, poor income, and working in a job increased the risk of suicide among these patients. It can be suggested that efforts for improving stress management in patients during the post-pandemic period may be effective in reducing the risk of suicide.