Background: Lifetime methamphetamine use among adolescents is estimated to be between 5% and 10%. Youth substance use in general is known to be associated with risky sexual behaviors, but the effect of methamphetamine use on recent risky sexual behaviors and adolescent pregnancy has received little attention. The purpose of this analysis was to evaluate the association between lifetime methamphetamine use and recent (past 3 months) risky sexual behaviors and lifetime adolescent pregnancy, adjusting for other substance use. Methods: We analyzed data from the 2003 National Youth Risk Behavior Survey, a school-based paper-and-pencil survey that assesses risky health behaviors among a nationally representative sample of 9th- to 12th-grade students. Multivariable logistic regression was used to calculate adjusted odds ratios (AORs) to examine the association between methamphetamine use and being recently sexually active, having 2 or more recent sex partners, and ever being pregnant or getting someone pregnant. Results: Lifetime methamphetamine use was reported by 7.6% of students. After adjustment for demographic covariates and lifetime use of cigarettes, alcohol, marijuana, and other illicit drugs, lifetime methamphetamine use was associated with recent sexual intercourse (AOR = 1.8, 95% confidence interval [CI] = 1.5-2.3), having 2 or more recent sex partners (AOR = 3.0, 95% CI = 2.2-4.2), and ever being pregnant or getting someone pregnant (AOR = 2.9, 95% CI = 2.1-3.9). Conclusions: Adolescent methamphetamine use is common and is associated with recent risky sexual behaviors and adolescent pregnancy. Prevention strategies for high school students should integrate education on substance abuse, pregnancy, sexually transmitted infections, and human immunodeficiency virus. (Contains 4 tables.)