Suicide and suicidal behavior are complex health conditions. The various factors such as psychological, social, and biological are associated with suicide and suicidal behavior. Despite its potential significance, only few studies have explored the relationship between nutrition and suicidal behavior. Studies have consistently shown that nutritional deficiencies are prevalent among persons with mental disorders, who are also at increased risk of suicidal behavior. This chapter explores the complex interplay between nutrition and suicidal behavior, the underlying mechanisms, and discussion on potential prevention and treatment strategies. The chapter concludes by highlighting critical areas for future research in suicide and nutrition.