Reviews of literature made manifest that native English speakers who were research participants in many studies on disagreements were Americans (e.g., Beebe & Takahashi, 1989; Takahashi & Beebe, 1993; Dogacay-Aktuna & Kamisli 1996; Rees-Miller, 2000; Guodong & Jing, 2005; Chen, 2006). The excessive use of Americans as research participants presented a rather restricted view on how the disagreements could be performed by native speakers of English. These studies exhibited that Americans in a classroom context normally began their student-lecturer disagreements with a positive comment (e.g., "The idea is interesting but…"). Based on these results, the ESL/EFL learners might over-generalize from Americans to other groups of native English speakers and consequently postulate that all native English speakers initiate their student-lecturer disagreements with an optimistic remark. This current study chose a group of 13 Canadians and investigated their disagreement strategies in the identical context. The data were collected by videotaping the participants' classroom for three hours every week for five consecutive weeks. Results showed that the participants normally disagreed with their lecturer explicitly but mitigated their explicit disagreements with some justification (e.g., "No because…"). The findings underscored that Americans and Canadians did not normally use the same disagreement strategies in the classroom context. If future studies increasingly use British English, Australians, New Zealanders or South Africans as research participants and investigate their expressions of student-lecturer disagreement, the ESL/EFL learners will become keenly aware of differences across all native English speakers. In other words, they will be able to avoid over-generalizing from Americans to other native English speakers.