Abstract This article examines teacher ideologies and multilingual practices in teaching Arabic as a heritage language in the USA. Using indexicality and its nexus to language ideologies, it identifies the key index values assigned to Standard Arabic (SA) and how these shape teacher positioning for teaching Arabic heritage. The article also analyzes the extent to which these ideologies are congruent or incongruent with their classroom practices. The findings of in-depth semi-structured interviews showed teachers’ veneration of SA with representations that index ‘perfection’, ‘majesty’, ‘purism’, and ‘generosity’. Although teachers seemed tolerant of using Arabic dialects strategically, their overall positioning supported teaching SA and minimized teaching dialects. Drawing on data from a larger corpus of around 25 hr of classroom video recordings, teachers showed ubiquitous multilingual and multidialectal practices in classroom discourse. With its dual focus on language ideologies and practices, this article enriches the discussion about the idealization of SA (fuṣḥatopia) as restricting the potential of Arabic dialects as important resources for learning SA. It also disrupts the linguistic hierarchy between SA and the dialects.