Introduction: Effective communication often involves expressing disagreement while maintaining social harmony, which is influenced by cultural and linguistic norms. Native speakers of English typically employ various politeness strategies in their disagreement speech acts. However, Iraqi EFL learners may navigate these strategies differently due to variations in cultural norms and language proficiency. Therefore, the current study aimed to contrastively analyze the way Iraqi EFL learners and native English speakers perform the speech act of disagreement in light of politeness. Methodology: In this regard, a discourse completion test (DCT) was administered to 66 participants, comprising 33 Iraqi EFL students studying English as a foreign language (TEFL) and 33 native English speakers. The DCT was made up of scenarios that mirrored real-life circumstances in order to provoke responses from people who disagreed with them. Brown and Levinson’s (1987) theory of politeness was employed to analyze participants’ utterances. Results: The findings indicated that while expressing disagreement with people of higher, participants in both groups were more concerned with keeping their interlocutors’ positive faces. Furthermore, the study findings indicated that despite differences in the two groups of participants, Iraqi EFL learners utilized positive indirect politeness strategies more frequently than English native speakers. On the other hand, English native speakers applied direct and negative politeness strategies. Conclusion: Generally, the findings indicated that both groups tended to use the most direct type of disagreement as the social distance and power relation decreased.