Self-compassion has been generally recognized as a protective psychological factor against mental illnesses. However, its protective value against addictions remained unclear. To address this research gap, the current study explores the associations between self-compassion and both alcohol use disorder [AUD] and gambling disorder [GD] tendencies under the framework of self-compensation model of addiction. Data from a convenience sample of 682 adult past-year gamblers and drinkers were collected via an online survey in Hong Kong, China. Results of a series of mediation, moderation, and moderated mediation analyses showed a double-edged effect of self-compassion on addiction: the mindfulness facet of self-compassion was associated with lower levels of AUD and GD tendencies through suppressing self-compensation motivation for drinking and gambling, whereas its self-kindness facet was positively associated with both AUD and GD tendencies via increased self-compensation motivations among participants under high stress. Common humanity was not related to risk for AUD or GD. These findings indicate the conditional risk-enhancing effects of self-kindness may counteract the protective effects of mindfulness against both substance and behavioral addictions. Future addiction prevention programs may monitor participants’ stress, as well as self-kindness levels, and focus on cultivating mindfulness, especially when utilizing self-compassion-based interventions.