This study explores Thai newspaper commentaries focused on the disruption of the ASEAN Summit on April 11, 2009. The objective of the present study is to examine lexical strategies employed by appraisal theory, a tool to analyze the attitudes expressed in newspaper commentaries in greater depth. The data of this study was obtained from thirty-two newspaper commentaries retrieved from nine online newspapers: Banmuang, Dailynews, Khaosod, Komchadluek, Manager, Matichon, Naewna, Posttoday and Thaipost. The results reveal that the commentators made use of both positive and negative emotional responses through either adjectives, noun phrases or verb phrases in terms of affect, which deals with the expression of emotion. Under judgement, which deals with moral assessments of behavior, the commentators judged people’s behavior either positively or negatively through either adjectives, adverbs, noun phrases, verb phrases or metaphors as well as appreciation which deals with aesthetic assessments. With respect to attitude, a resource of language that enables commentators to express their attitude, the Thai newspaper commentaries examined contained predominantly negative evaluative lexis. Negative lexical items make the commentaries more intense and emotional for readers because of the news value of negativity, which focuses on political conflict in the Thai context. In the graduation category of appraisal, which is concerned with gradability, the explicit attitudes occurred with grading up rather than grading down. In the force sub-category, which relates to adjusting the degree of an evaluation, the commentators achieved intensification through isolation, infusion, repetition and metaphor, and achieved quantification through quantity, which is encoded as number and extent in time and space in order to enhance readers’ agreement with the commentators’ attitudes. Under focus, which relates to adjusting the boundaries of a categorical meaning, most stances represent a sharpening of the attitudinal entity rather a softening one.