Résumé : Following the call for further research on the organisational side of complaint handling, this research aims to explore actual firms’ complaint handling practices with a special focus on the role of politeness in firms-complaints interactions. This research is largely based on a dataset of naturally occurring exchanges obtained from the online public forum Les Arnaques – “The Scams” (www.lesarnaques.com). The setting is similar to a double-deviation scenario: the consumers had already complained once through the relevant company but were unsatisfied with the response. By lodging their complaint on the forum they seek mediation to obtain satisfaction in a second attempt.As a first step, an enhanced conceptualisation of politeness in relation to the concept of complaint handling was proposed and tested. Sociolinguistics theories were used (Goffman’s theory of face, Grice’s maxims) and a quantitative analysis was conducted, to discover how the consumer’s perception of a firm’s politeness is influenced. This conceptualisation, new for the marketing literature, led to proposing a more accurate framework to assess the politeness-related practices of firms when handling complaints.In a second step, this new conceptualisation of politeness was integrated within a larger framework to assess firms’ practices on several dimensions. Justice theory was used as a starting point to define practices within each dimension of justice: distributive, procedural and interactional. Literature from other disciplines (sociology, linguistics, psychology) was used to define precisely the different constructs belonging to the three dimensions. For instance the “empathy” construct was split, based on the literature in psychology, into cognitive and affective empathy, which allowed the precise identification of the occurrences of empathy in firms’ answers. The effects of 33 dimensions were analysed, using a sample of 523 exchanges archived from the forum Les Arnaques. A multinomial regression analysis showed that the most significant antecedent of post-complaint satisfaction was a new dimension, not previously found in the literature: the provision of evidence that the complainant’s problem had been, or was about to be, solved.In a third step, exploratory research was undertaken to investigate possible collinearity effects between three of the most often cited constructs of interactional justice: empathy, politeness and apology. Using the coding guide previously developed, and the exchanges coded, results showed some overlap between the constructs and high Cramer’s V, indicating a redundant concept. Recommendations were provided as to what should be measured, and how, so that researchers can avoid such effects in the future.The naturally occurring exchanges used for the first three steps revealed that firms’ answers were often impolite and littered with spelling mistakes. Two subsequent papers explored the phenomena of grammaticality and im/politeness.In a fourth step, the effects of grammaticality and politeness on customers’ perceptions and behavioural outcomes were explored. Specifically, a survey was conducted to determine the effect of grammar/spelling mistakes and politeness on the perception of professionalism and on repurchase intention. Results from a PATH analysis showed that politeness and grammaticality had low or no direct effect on loyalty. However, indirect effects mediated by professionalism were strong, indicating that consumers’ repurchase intentions depend on a firm’s perceived professionalism.Finally, in a fifth step, efforts were focused on impoliteness and on the role the communication channel plays in expressions of impoliteness. Impolite answers found on the online forum were compared with offline responses obtained in a field experiment. Unexpectedly, results from a discourse analysis showed that the highest levels of impoliteness were not reached in online exchanges, where users can hide behind anonymity, but in postal exchanges. In particular, we found that some companies returned the original complaint letter, riddled with insults. This led us to propose that impoliteness not only a matter of content (the words being used) but also of form. In this case, the letter seemed to act as a catalyst for conflict and was the trigger for verbal violence.In terms of marketing, the following work contributes to theory building by proposing a new conceptualisation of politeness, by defining a more precise framework to analyse firms’ complaint handling practices, and by uncovering collinearity effects that may have impeded previous results. The last two steps of this thesis bring exploratory insights by showing the effects of politeness and grammaticality on consumers’ perceptions.Besides contributing new academic insights, one goal of this thesis was also to serve the business community. The findings show that politeness matters: not only does politeness help reach short-term goals like post-complaint satisfaction, but it also contributes to long-term effort, like forging a professional identity and fostering customer loyalty.