ABSTRACT: Although text-messaging interventions are effective for smoking cessation, few target teens in the USA and little is known about their effectiveness. The purpose of this manuscript is to examine correlates of dropout, response to smoking status prompts, and abstinence rates among subscribers of SmokeFreeTeen, a free, publicly available text-messaging smoking cessation intervention sponsored by the National Cancer Institute's SmokeFree.Gov initiative, on quit day through 1 month follow-up. In a sample of teens (N = 2,685), aged 13-19, we examined demographics, smoking frequency, cigarettes smoked per day, prequit intervention time (i.e., maximum of 14 days of prequit day preparation), and number of quit attempts as correlates of response and abstinence rates among program initiators (i.e., participants who reached quit day but dropped out on or before intervention end) and completers (i.e., participants who reached quit day and completed the intervention). We also conducted Cox regression analysis of time from quit day to dropout by daily and nondaily smoking status. Two-thirds (n = 1,733, 64.54%) dropped out before the intervention ended, with dropout rates peaking on quit day (n = 289, 13.10%). Response rate to smoking status prompts remained below 30% throughout the intervention. At intervention end and 1 month follow-up, abstinence was 2.63% and 2.55% among program initiators, whereas abstinence was 6.09% and 6.01% among program completers. Dropout, response, and abstinence rates did not consistently differ by subscriber characteristics. Prequit time was associated with decreased likelihood of dropping out (adjusted hazards ratio: 0.94, confidence interval [CI]: 0.93-0.95), responding to smoking status prompts (adjusted odds ratio [aOR]: 0.94, CI: 0.92-0.96), and being abstinent (aOR: 0.96, CI: 0.93-0.99) on quit day. Two or more quit attempts were associated with increased response (aOR: 1.61, CI: 1.16-2.23) and abstinence (aOR: 1.91, CI: 1.25-2.92) rates on Day 7. In a first assessment of SmokeFreeTeen outcomes, we document high dropouts and low response and abstinence rates. SmokeFreeTeen produced abstinence rates lower than comparable text-messaging interventions targeting teens and young adults. Improving SmokeFreeTeen's reach, engagement, and effectiveness is needed.