Personalized sticker is a new form of graphicon in mobile instant messages that has emerged in recent years. Personalized stickers allow users to create visual content freely with very few limitations which, in turn, has significantly increased their popularity in recent years. This study investigates the difference between using personalized and nonpersonalized stickers in promoting social presence under positive and negative emotional valence based on a three-dimensional model of social presence, which measures the sensory, affective, and cognitive social presence. A 2 (type of sticker) × 2 (emotional valence) experimental design was employed to investigate the main effects of the type of stickers and emotional valence as well as their interaction effect on social presence. Forty-seven participants aged 18–26 from Hong Kong were recruited for this study. Two-way ANOVA was employed to analyze the data. Results showed that using personalized stickers had significantly higher sensory and affective social presence than the nonpersonalized sticker condition. Surprisingly, participants who used personalized stickers reported a significantly stronger sense of social presence than those who used nonpersonalized stickers under negative emotional valence conditions. Implications for research and practice in online/digital learning environment are also discussed.