Jumping to conclusions (JTC) and impaired social cognition (SC) affect the decoding, processing, and use of social information by people with psychosis. However, the relationship between them had not been deeply explored within psychosis in general, and in first-episode psychosis (FEP) in particular. Our aim was to study the relationship between JTC and SC in a sample with FEP. We conducted a cross-sectional study with 121 patients with FEP, with measures to assess JTC (easy, hard, and salient probability tasks) and SC (emotional recognition, attributional style, and theory of mind). We performed Student’s t-test and logistic regression in order to analyse these associations.We found a statistically significant and consistent relationship of small-moderate effect size between JTC (all three tasks) and impaired emotional recognition. Also, our results suggest a relationship between JTC and internal attributions for negative events. Relationships between JTC and theory of mind were not found. These results highlight the importance of psychological treatments oriented to work on a hasty reasoning style and on improving processing of social information linked to emotional recognition and single-cause attributions.