Résumé : Positioned within the context of online complaint-handling, the present study aimed to examine the potentially mediating role of perceived professionalism in the relationships between message content (grammaticality) and form (politeness) on the one hand and customer loyalty on the other. A path analysis revealed that: (1) grammaticality impacts upon loyalty indirectly through the message recipients’ perceptions of the credibility and competence of the sender; (2) politeness impacts upon loyalty directly as well as indirectly through the message recipients’ perceptions of the credibility and competence of the sender, and (3) both perceptions of credibility and perceptions of competence strongly (positively) impact upon customer loyalty. These findings suggest that in an on-line, text-based complaint-handling context, the perceived professionalism of firm representatives plays a key explanatory role in the relationship between message form and content on the one hand and consumers’ repurchase intentions on the other. Implications for practitioners are discussed and recommendations formulated to better handle complaints enhance odds of repurchase intentions.