Disciplinary literacy instruction during kindergarten through second grade enables students to begin developing facility with consuming, producing, and learning from texts in academic disciplines across their school careers and for full civic participation. Extant intervention studies and descriptions of practice in the primary grades offer understanding of disciplinary literacy instruction when it is enacted with researchers' help and/or by teachers with expertise in disciplinary literacy. To address disciplinary literacy in the primary grades, insight into what primary teachers focus on and how they support students' disciplinary literacy learning during their naturally-occurring instruction is needed. This exploratory collective case study examined the disciplinary literacy learning opportunities available in first-grade teachers' instruction. Participants included four teachers in four elementary schools situated in a large city in the Midwest. Audio records and field notes were collected over a period of five months during teachers' literacy instruction. Open coding, progressive refinement of codes, and categorical analyses revealed limited instructional emphasis on disciplinary literacy. When learning opportunities were observed, teachers' foci and support centered on the social foundations of disciplinary literacy and included sharing of information and student practice. Also, problematic disciplinary literacy learning opportunities were noted. This study underscores the urgent need for additional attention to disciplinary literacy as it is situated within the primary grades, with particular import for how first-grade teachers enact disciplinary literacy instruction.