This year-long multiple case study examines how three elementary-level ESL teachers understood their advocacy for emerging bilinguals, what tensions arose during their advocacy, and how they dealt with those tensions. Interviews, teaching artefacts, and observations were analyzed using a theoretical model informed by third space theory and existing research on teachers' critically conscious advocacy. The way that these teachers conceptualized their advocacy (i.e. non-critical, critically emerging, and critically conscious) was tied to the tensions that they encountered as advocates (i.e. advocacy as core versus marginal ideas; advocacy beliefs versus actions; ideological alignment versus misalignment). Teacher participants often dealt with tensions by engaging with stakeholders in third spaces, which are hybrid zones between formal and informal spaces of social interactions. Some of the actions that teacher participants took within third spaces included co-constructing new cultural knowledge with emerging bilinguals' families; building bridges between the school and their students' communities; and reimagining alternative practices. This study shows that third spaces can help teachers and stakeholders to jointly identify tensions stemming from divergent goals and help them to collaborate in advocating for emerging bilinguals.