Muscle Dysmorphia (MD) is a severe subtype of body dysmorphic disorder (BDD) that shares symptomatic overlap with eating disorders. Although associations between eating disorders/BDD and suicidality are well documented, research has rarely examined associations between MD symptoms and suicidality, which is concerning given MD is associated with additional suicide risk factors compared with these disorders. Further, existing associations between MD symptoms and suicidality have yet to establish temporal ordering for these relationships. Therefore, the current study investigated longitudinal relationships between MD symptoms and suicidal ideation to establish the direction of the MD-suicidality relationship.