Regular physical exercise lowers the risk of all-cause mortality and various chronic diseases. New technologies, such as smartphones and social media, have been used successfully as health promotion tools in college populations. The purpose of this study was to conduct a systematic review of studies examining the effectiveness of interventions that used modern technologies, as with social media or text messaging, to promote physical activity or reducing sedentary behavior in college students. The systematic review was conducted on the PubMed and SCOPUS databases, considering studies published from 2012 to 2022. For a total of 19 articles selected, an evidence table was drawn up, and the quality of the studies was assessed using the PRISMA checklist. The interventions differed enormously in design, from the strategies implemented to the types of outcome considered. Fifteen of the 19 studies demonstrated an improvement in participants’ physical activity levels, 3 studies found no such improvement, and 1 reported a worsening of baseline activity levels. Interventions to improve college students’ physical activity levels through the use of social media and/or text messaging tend to be effective. However, many factors can influence the effectiveness of such interventions. For example, a gender-related difference emerged in student participation, and the interventions proved more effective if they were accompanied by the creation of social groups.