Although suicide is the second leading cause of death among Asian American adolescents, there is a dearth of studies examining overall and possible sex and sexual orientation disparities in the trends in suicidal behaviors among Asian American adolescents. Such information is crucial to inform targeted efforts of suicide prevention among Asian American adolescents. To examine temporal trends and sex and sexual orientation disparities in trends of nonfatal suicidal behaviors in Asian American adolescents from 1991 through 2019. This cross-sectional study used data from the national Youth Risk Behavior Survey from 1991 through 2019, analyzing a representative sample of US adolescents in grades 9 through 12 using a 3-stage cluster-sampling design. Data were analyzed from October through November 2020. Calendar year, sex, sexual identity, sex of sexual contact, and interaction terms of these factors. Crude prevalence and annual percentage changes (APCs) in self-reported suicidal ideation, suicide plan, suicide attempts, and injury by suicide attempt for the overall sample and by sex, sexual identity, and sex of sexual contacts were calculated. Sexual minorities were defined as individuals whose sexual identity was gay or lesbian, bisexual, or not sure. Among 7619 Asian Americans who participated in the Youth Risk Behavior Survey from 1991 to 2019 (mean [SD] age, 16.09 [1.29] years; 3760 [47.1%] female adolescents), 1576 individuals completed the sexual identity and behaviors questions after 2015 (mean [SD] age, 15.97 [1.28] years; 810 [49.2%] female adolescents). From 2009 through 2019, there was a 1.3-fold (95% CI, -0.8 to 3.3; P = .22) increase in suicide attempts and a 1.7-fold (95% CI, -2.6 to 5.9; P = .45) increase in injury by suicide attempt among Asian American female adolescents, although these increases were not statistically significant. Among 39 Asian American adolescents who identified as gay, lesbian, or bisexual or who were attracted to and had sexual contact with partners of the same sex or both sexes, compared with 1556 Asian American adolescents who were heterosexual, prevalence was greater for suicidal ideation (24 individuals [68.2%] vs 223 individuals [15.0%]; P < .001), suicide plan (15 individuals [57.7%] vs 179 individuals [11.9%]; P < .001), suicide attempts (14 individuals [41.0%] vs 74 individuals [5.5%]; P < .001), and injury by suicide attempt (5 individuals [17.6%] vs 23 individuals [1.7%]; P < .001) between 2015 and 2019. These sexual minorities identified by sexual identity and sexual contact also had an increasing rate over this period in suicide plan (APC, 10.5%; 95% CI, 4.4% to 16.9%; P < .001). This study found significant increases in rates of suicide plan among Asian American adolescents who were sexual minorities identified by sexual identity and sexual contact together. These findings suggest that suicide screening needs to inquire about sexual minority status in terms of sexual identity and sex of sexual contact when identifying Asian American adolescents who are at risk for suicidal behaviors. Culturally relevant suicide-prevention programs addressing unique risk and protective factors, racial discrimination, and sexual orientation-related stigma may be needed for Asian American adolescents.