This study examined the factors associated with internet gaming disorder (IGD) and online gambling disorder (OGD), and explored how these factors might influence the severity of IGD and OGD. A total of 273 first-year psychology students aged 18 to 25 years completed a survey. About 32.6% of participants had problematic internet gaming, and 1.8% met the criteria for IGD. About 7% had problem online gambling, and 2.2% met the criteria for OGD. About 7% reported both problem gaming and gambling. More severe IGD symptoms were linked to male gender, social network/Internet use, irrational beliefs, and emotion regulation difficulties. More severe OGD symptoms were linked to male gender and irrational beliefs. Being male was linked to more severe IGD and OGD symptoms through irrational beliefs and higher levels of social network/internet use. Younger age was associated with more severe IGD symptoms through difficulties with emotion regulation.