•This study examined the effect of internal communication on positive emotional culture.•The impact of positive emotional culture on supportive employee behaviors was also explored.•A web survey was conducted with 506 employees in the U.S.•Results showed symmetrical communication and responsive leadership communication cultivated positive emotional culture.•Positive emotional culture of joy, companionate love, pride, and gratitude fostered organizational citizenship behavior and employee advocacy. The study surveyed 506 employees in the United States to test the effect of internal communication (i.e., corporate-level symmetrical and leadership-level responsive communications) on fostering a positive emotional culture characterized by companionate love, joy, pride, and gratitude. In addition, we tested the interplay between corporate internal communication and a positive emotional culture and its influence on supportive employee behaviors, specifically, organizational citizenship behavior (OCB) and employee advocacy. Results indicated that symmetrical communication and responsive leadership communication cultivated a positive emotional culture in organizations. Such culture also fostered employee OCB and advocacy. Moreover, corporate symmetrical communication directly and positively influenced employee OCB. Finally, this study found that employee OCB positively affected employee advocacy. The theoretical and practical implications of the findings for public relations scholars and practitioners were discussed.