This study discusses how the broad use of the Thai expression mai-pen-rai (It's not substantial), classified into four functional categories, -comprising a reply to apologizing and thanking, a refusal strategy with regard to an offer, a remark of solace, and a strategy to end verbal conflict-, is tightly linked to the Buddhist notion of Tri Laksana, by which nothing is really important. The uses of mai-pen-rai thus strive to disengage the hearer from her/his worry by alluding to Buddhist ideology. .