Cyberbullying is associated with negative mental health outcomes including adolescent suicidal ideation. This requires effective and accessible preventive efforts. Healthy lifestyles are factors adolescents themselves can modify that may lower their risk of suicidal ideation. The aim of this study was to examine associations between physical activity, (outdoor) sport participation, a healthy diet, higher sleep duration and low levels of smoking and alcohol use, and suicidal ideation when faced with cyberbullying. A cross-sectional survey was administered in 2014-2015 to 1037 adolescents (12-18 years, M age = 15; 50% girls) in Flanders, Belgium. Logistic regression analyses were conducted to assess direct effects of cyberbullying involvement (victim, perpetrator, bystander) on suicidal ideation, and interaction effects between cyberbullying involvement, healthy lifestyles and suicidal ideation. Results showed that cyberbullying victimization, perpetration and bystanding were associated with higher suicidal ideation, but that the association with cyberbullying perpetration disappeared when corrected for other cyberbullying involvement forms. More physical activity, sleeping longer, more often taking a healthy diet and lower levels of smoking were associated with lower suicidal ideation. Some associations of healthy lifestyles with suicidal ideation disappeared at higher levels of cyberbullying involvement. Low alcohol consumption and (outdoor) sport participation were not associated with suicidal ideation, and sport participation was even associated with higher suicidal ideation at low levels of cyberbullying involvement. These findings suggest a novel approach to suicide prevention may be warranted, by strengthening healthy lifestyles as factors that adolescents themselves can modify to increase their resilience and reduce suicidal ideation.