ABSTRACT Emotionally overheated social media discussions cause many harms both to the individuals participating in the discussion and to the wider society. To support emotion regulation in social media discussions, the strategy of affect labelling is explored. Two experiments were run to study the effects of emotion labels presented with social media messages on participants’ emotional responses to the messages. Altogether 84 participants read emotional social media messages presented without and with emotion labels (Experiment 1, N = 39), and without labels and with emotion / control labels (Experiment 2, N = 45) and rated their subjective emotional valence. Results show that the ratings of valence were significantly higher for the positive messages presented with label than for the messages presented as such without emotion label or presented with a control label. In addition, the results of the second experiment show that the negative social media messages were experienced as more negative when the messages were presented with an emotion label than without emotion label or with control label. The results suggest that affect labelling of social media messages is an ineffective strategy to down-regulate emotions but could be used to support and strengthen positive emotions.