The study explores the notion of HP Grice’s Four Maxims as realized in mobile phone discourse, particularly text messaging or short messaging service (SMS). Using data from selected Filipino SMS conversations, observance and nonobservance of the maxims are described, and possible effects on the conversation posited. The results revealed that texters typically observe the maxims, although there were occasional instances of non-observance. Non-observance appeared nonintentional, and possibly constrained by the limited number of letters or characters that mobile phones accommodate, as well as by the style of particular texters. The maxims of quantity and relevance appeared to be the most observed of the four maxims.