This research aims to investigate the problematic levels of internet usage and smartphone addiction as predictors of university students' happiness levels. The research was carried out using the relational screening method, which is among the quantitative research methods. The research study group consisted of 340 university students, in which 229 were females (67.4%), and 111 were males (32.6%), studying at various departments of a state university, and voluntarily agreeing to partake in the research. In the research; "Oxford Happiness Scale -- Short Form", the "Problematic Internet Usage Scale", and "Smartphone Addiction Scale -- Short Form" were all adapted into Turkish and implemented. From the results of the research, there was a strong negative correlation between the levels of happiness of university students and problematic internet usage and smartphone addiction. Furthermore, it was found that university students' problematic internet use and smartphone addiction levels explained 14% of their level of happiness. The results of the study were discussed and recommendations presented in light of the literature.