Purpose: The primary aims are to (1) obtain representative prevalence estimates of suicidal thoughts and behaviors (STB) among college students worldwide and (2) investigate whether STB is related to matriculation to and attrition from college. Methods: Data from the WHO World Mental Health Surveys were analyzed, which include face-to-face interviews with 5750 young adults aged 18–22 spanning 21 countries (weighted mean response rate = 71.4%). Standardized STB prevalence estimates were calculated for four well-defined groups of same-aged peers: college students, college attriters (i.e., dropouts), secondary school graduates who never entered college, and secondary school non-graduates. Logistic regression assessed the association between STB and college entrance as well as attrition from college. Results: Twelve-month STB in college students was 1.9%, a rate significantly lower than same-aged peers not in college (3.4%; OR 0.5; p OpenSPiltSPi 0.01). Lifetime prevalence of STB with onset prior to age 18 among college entrants (i.e., college students or attriters) was 7.2%, a rate significantly lower than among non-college attenders (i.e., secondary school graduates or non-graduates; 8.2%; OR 0.7; p = 0.03). Pre-matriculation onset STB (but not post-matriculation onset STB) increased the odds of college attrition (OR 1.7; p OpenSPiltSPi 0.01). Conclusion: STB with onset prior to age 18 is associated with reduced likelihood of college entrance as well as greater attrition from college. Future prospective research should investigate the causality of these associations and determine whether targeting onset and persistence of childhood–adolescent onset STB leads to improved educational attainment.