Because smartphones are ubiquitous in our society, and undergraduate students use smartphones extensively, it is necessary to understand how undergraduates can be protected from malicious hacker attacks, viruses, and malware. This quantitative study explores the influence of Protection Motivation Theory (PMT) constructs on security behaviors of undergraduate students. The primary focus of this quantitative study is to answer our primary research question: to what extent do the independent PMT variables (perceived threat severity, perceived threat vulnerability, self-efficacy, response efficacy, and response cost) explain undergraduate students' employment of smartphone security measures? The findings suggest that although all hypotheses were not supported by the analysis; however, self-efficacy and perceived threat vulnerability showed a statistically positive association with several smartphone security measures. However, none of the constructs showed a statistically significant association with using unsecured Wi-Fi in public places. The practical implications of the findings are for industry to focus on better design of smartphone hardware and software (such as antivirus apps) to protect users, and to increase self-efficacy among smartphone undergraduate users through training and education.