Latino adults experience multiple barriers to health care access and treatment that result in tobacco-related disparities. Mobile interventions have the potential to deliver smoking cessation treatment among Latino adults, the highest users of mobile technologies. Is Decídetexto, a culturally accommodated mobile health intervention, more effective for smoking cessation compared with standard care among Latinx adults who smoke? A two-arm parallel group randomized clinical trial (RCT) was conducted in Kansas, New Jersey, and New York between October 2018 and September 2021. Eligible Latino adults who smoke (n= 457) were randomly assigned to Decídetexto or a standard care group. The primary outcome was biochemically verified 7-day smoking abstinence at week 24. Secondary outcomes included self-reported 7-day smoking abstinence at weeks 12 and 24 and uptake and adherence of nicotine replacement therapy (NRT). Participants' mean age was 48.7 (SD, 11.1) years, 45.2%were female, and 50.3%smoked≥10 cigarettes per day. Two hundred twenty-nine participants were assigned to Decídetexto and 228 to standard care. Treating those lost to follow-up as participants who continued smoking, 14.4%of participants in the Decídetexto group were biochemically verified abstinent at week 24 compared with 9.2%in the standard care group (OR, 1.66; 95%CI, 0.93-2.97; P= .09). Treating those lost to follow-up as participants who continued smoking, 34.1%of the participants in the Decídetexto group self-reported smoking abstinence at week 24 compared with 20.6%of participants in the standard care group (OR, 1.99; 95%CI, 1.31-3.03; P< .001). Analyzing only participants who completed the assessment at week 24, 90.6%(174/192) of participants in the Decídetexto group self-reported using NRT for at least 1day compared with 70.2%(139/198) of participants in standard care (OR, 4.10; 95%CI, 2.31-7.28; P< .01). Among Latino adults who smoke, the Decídetexto intervention was not associated with a statistically significant increase in biochemically verified abstinence at week 24. However, the Decídetexto intervention was associated with a statistically significant increase in self-reported 7-day smoking abstinence at weeks 12 and 24 and uptake of NRT. This RCT provides encouragement for the use of Decídetexto for smoking cessation among Latino adults. ClinicalTrials.gov identifier: NCT03586596.