Background: Drawing on the intolerance of uncertainty model, this study aimed to examine whether intolerance of uncertainty and emotion regulation difficulties (in terms of impulse control difficulties and limited access to emotion regulation strategies) contributed to individual differences in gambling urge and involvement. Methods: Convenience sampling was used to recruit Chinese adult participants who had engaged in buying lottery tickets and other gambling activities in the past year. They were asked to complete an anonymous questionnaire survey, and a total of 580 valid cases (M = 34.07, SD = 13.36; 50.4% female) were collected for data analysis. Results: Path analysis showed that the total effect of intolerance of uncertainty on gambling urge and involvement was significant and positive. However, only impulse control difficulties and not limited access to emotion regulation strategies fully mediated the effect of intolerance of uncertainty. Conclusions: As the first study to apply the intolerance of uncertainty model to real-life gambling, it found that individuals’ intolerance of uncertainty and impulse control difficulties contributed to more gambling urge and involvement. Improving emotion regulation skill (e.g., impulse control training) may, therefore, be considered in programs for promoting responsible gambling among Chinese gamblers.