University students are a high-risk population with problematic online behaviours that include generalized problematic Internet/smartphone use and specific problematic Internet uses (for example, social media or gaming). The study of their predictive factors is needed in order to develop preventative strategies. This systematic review aims to understand the current state of play by examining the terminology, assessment instruments, prevalence, and predictive factors associated with problematic smartphone use and specific problematic Internet uses in university students. A literature review was conducted according to the PRISMA guidelines using four major databases. A total of 117 studies were included, divided into four groups according to the domain of problem behaviour: problematic smartphone use (n = 67), problematic social media use (n = 39), Internet gaming disorder (n = 9), and problematic online pornography use (n = 2). Variability was found in terminology, assessment tools, and prevalence rates in the four groups. Ten predictors of problematic smartphone use, five predictors of problematic social media use, and one predictor of problematic online gaming were identified. Negative affectivity is found to be a common predictor for all three groups, while social media use, psychological well-being, and Fear of Missing Out are common to problematic smartphone and social media use. Our findings reaffirm the need to reach consistent diagnostic criteria in cyber addictions and allow us to make progress in the investigation of their predictive factors, thus allowing formulation of preventive strategies.