This study explored whether attributions for negative partner behavior mediate the association between insecure attachment and negative couple communication, using both self-report and observational data. A sample of 59 married and cohabiting Australian couples completed self-report measures of attachment, attributions, and communication; were videotaped participating in two 10-min problem-solving discussions; and were assessed on their attributions during the discussions using video-mediated recall. Multilevel modeling found that female attachment insecurity was the most consistent predictor of self-reported and observed couple communication, and negative attributions mediated the association between attachment and self-reported couple communication. These findings suggested that attachment insecurity increased the likelihood that negative attributions were generated, which, in some cases, then influenced the style of communication each partner reported.