Professional learning communities (PLCs) have become a popular strategy in various forms (e.g., data teams, grade-level teams) and with various champions (e.g., district leaders, university researchers, teacher advocates). Although well-implemented PLCs have been shown to distribute leadership, the tension between democratic inquiry processes and the demands of accountability remain understudied. This study asks how teacher inquiry is situated within conflicting school priorities and the impact of competing power structures on PLCs through a case study of a teacher inquiry initiative at 6 urban elementary and middle schools in the US. Data were collected over 3 years of PLC implementation. District officials, principals, reform coaches, and teachers at each setting participated in more than 300 interviews, regular site visits, and annual teacher surveys. The influences of power structures--such as district mandates, accountability pressures, and principal leadership--emerged as strong themes in teacher narratives of what it means to "do" inquiry in their PLCs.