Research suggests the link between self-criticism and low social belonging is partially explained by lower expression of positive emotions (Luoma & Chwyl, 2020), however, it is not well understood why high self-critics (HSCs) express less positive emotions. The purpose of this study is to investigate the underlying mechanisms that might explain this reduced expression of positive emotions. Participants were recruited from an adult, community sample (N = 303). Participants came to the laboratory and were shown two short videos intended to reflect two different situations where social bonding might be possible, caregiving in response to another’s distress and responding with friendship/cooperation responses to another’s positive affect. They completed questionnaires pre- and post-video. We hypothesized that HSCs would respond to both videos with more negative emotions compared to low self-critics (LSCs) and would report more negative emotions in response to the caregiving stimulus compared to the friendship/cooperation stimulus. We further predicted HSCs would use more expressive suppression (ES) as an emotion regulation strategy and that their use of ES would be partially explained by increased negative emotions. Hypotheses were partially supported. Participants’ level of self-criticism positively predicted expressive suppression as well as negative emotions in response to both videos. HSCs reported higher shame across both videos, while low self-critics (LSC) reported variable shame across videos. HSCs’ increased use of ES was partially explained by their increase in negative emotions. These findings suggest HSCs may be using ES in response to contextually incongruent emotions. Clinical implications include providing HSCs with corrective emotional experiences in social-bonding contexts and helping them express their incongruent negative emotions in a safe setting.