OBJECTIVE Evidence is lacking regarding effective weight control treatments in pregnancy for ethnic minority women with obesity. This study evaluated whether a technology-based behavioral intervention could decrease the proportion of African American women with overweight or obesity who exceeded Institute of Medicine (IOM) guidelines for gestational weight gain. METHODS We conducted a two-arm pilot randomized clinical trial. Participants were 66 socioeconomically disadvantaged African American pregnant women (12.5 ± 3.7 weeks' gestation; 36% overweight, 64% obesity) recruited from two outpatient obstetric practices at Temple University between 2013 and 2014. We randomized participants to usual care (n = 33) or a behavioral intervention (n = 33) that promoted weight control in pregnancy. The intervention included: (1) empirically supported behavior change goals; (2) interactive self-monitoring text messages; (3) biweekly health coach calls; and (4) skills training and support through Facebook. RESULTS The intervention reduced the proportion of women who exceeded IOM guidelines compared to usual care (37% vs. 66%, P = 0.033). Intervention participants gained less weight during pregnancy (8.7 vs. 12.3 kg, adjusted mean difference: -3.1 kg, 95% CI: -6.2 to -0.1). No group differences in neonatal or obstetric outcomes were found. CONCLUSIONS The intervention resulted in lower prevalence of excessive gestational weight gain.