We investigate the efficacy of text messaging campaigns to remind students about and support them with key steps in the college search, application, selection and transition process. First, in collaboration with the College Board and uAspire, both national non-profit organizations, we implemented text-message based outreach and advising to students in over 700 US high schools that primarily serve large shares of low-income students. Second, we collaborated with several school districts in the state of Texas to implement a school-based version of the intervention. In the national sample, treatment students received outreach approximately once per month from uAspire counselors, whereas in the Texas sample, treatment students received outreach once every one to two weeks from their high school counselors. In both samples, outreach began in Spring 2015 and continued through September 2016. We tested these interventions with concurrent cluster randomized control trials with randomization at the school level. In contrast to the national version of the intervention, which tended to produce null effects, the school-based intervention yielded positive and significant impacts on several college-going steps and on college enrollment for certain subgroups. We discuss key differences between the two versions of the intervention that may have contributed to these divergent results.