Using a nationally representative sample of 16,296 high school students, we examined those who reported attempting suicide but did not report a suicide plan in the past 12 months. Results from logistic regression analyses showed that the 15% of attempters who did not report planning were as likely to receive medical treatment after their attempt as the attempters who did report planning. They also were more likely than nonideators and less likely than attempters who reported planning to report substance use and weapon carrying. All attempters, regardless of planning, were at high risk for fighting. Additional effort is needed to understand and prevent unplanned suicide attempts.