Drawn from a two-year critical ethnography, the author explores how Mexican-origin students in a U.S. southwest charter high school resisted Spanish heritage language instruction. Resistance was rooted in students' perception that their teacher unfairly characterized their linguistic and social identities. Students also constructed their non-native Spanish teacher to be a Spanish-language learner, disqualifying her to teach their heritage language, despite her proficiency. Misunderstandings arose from teacher's and students' limited imaginings of Spanish-language discourse communities.