Head and neck cancer (HNC) patients and their spouses experience communication problems and high rates of emotional distress. Couple-based interventions that encourage emotional disclosure hold promise for improving cognitive processing and distress in this population, but more research needs to examine when and for whom emotional disclosure is an effective coping strategy. In this observational study, 125 HNC patients (83% male) and their spouses were videotaped discussing a cancer-related concern in the laboratory. Discussions were coded with the specific affect coding system. Actor–partner interdependence models showed that patient expression of negative emotions (i.e., disdain, contentiousness, distress) was not related to his/her own or the spouse’s cognitive processing (assessed as reaction times to cancer and noncancer words on a computerized cognitive task administered immediately following the discussion). When spouses expressed support (e.g., interest, validation), they had better cancer- (effect size r = − 0.21) and noncancer-related cognitive processing (r = − 0.17), but patients did not. However, when spouses expressed disdain (e.g., contempt) and contentiousness (e.g., criticism, domineering), patients had poorer cancer- (r = 0.20–0.22) and noncancer-related cognitive processing (r = 0.19–0.26). Findings suggest consideration of the valence of affective expression and which partner is disclosing/listening before unilaterally encouraging HNC couples to openly express emotions as a means of alleviating distress.