The present study sought to examine the relation between borderline personality disorder (BPD) symptoms and empathic accuracy while improving on prior methodologies by using daily affect assessment in romantic partners. BPD symptoms were assessed in both members of 81 community couples who also reported on their own and their partner's negative and positive affect daily for 3 weeks. Data were analyzed using the Truth and Bias Model of Judgment, which allows the source of empathic accuracy to be parsed into partner affect (truth) and own affect (bias). Results provided evidence that individuals with higher BPD symptoms exhibited increased empathic accuracy for a partner's negative affect, particularly when partners also had higher BPD symptoms. The source of this accuracy stemmed more from bias forces than truth forces, indicating that participants' own affective states lead to more accurate judgments of partner affective state. The results suggest that this bias reduced the general tendency among participants to underestimate partner negative affect, thus leading to higher empathic accuracy. Overall, our results extend and provide support for previous research indicating that BPD symptoms are associated with heightened, not diminished, empathic accuracy. (PsycInfo Database Record (c) 2024 APA, all rights reserved).