Little focus has been paid to the role of nutrition among young people regarding mental health in sub-Saharan Africa. This study aimed to examine the relationship between nutrition and adolescent mental health for the promotion of effective school-based interventions in sub-Saharan African countries. The sample consisted of 14,968 11–17-year-old students in Botswana, Kenya, the Seychelles, Uganda, the United Republic of Tanzania, and Zambia participating in the Global School-Based Health Survey (2003–2007). Using bivariate logistic regression analysis, this study found across participating countries that: (1) lower hunger as a protective factor for depression, anxiety, loneliness, and suicidal ideation (except Zambia); (2) lower hunger as a protective factor for suicide attempts (except the United Republic of Tanzania); (3) lower hunger as a risk factor for suicide plan (except the United Republic of Tanzania); (4) higher fruit intake as a risk factor for depression, anxiety (except the United Republic of Tanzania), loneliness, suicidal ideation (except Zambia and Uganda), and suicide attempts (except Botswana); (5) higher fruit intake as a protective factor for suicide plan (except Botswana); (6) higher vegetable consumption as a risk factor for depression, anxiety (except the United Republic of Tanzania and Zambia), loneliness, suicidal ideation, and suicide attempts; and (7) higher vegetable intake as a protective factor for suicide plan. This study suggests school practitioners and school staff to articulate positive mental health by incorporating adequate nutrition components in school-based interventions. Further research should investigate whether such improvements to the nutrition components can foster positive youth mental health