This study examines which school factors schools report influence their (dis)continuation of lesson study, a professional development initiative, and how after a four-year, cross-school lesson study project ends. To examine this, the framework on three types of school factors (features of employment, malleable school processes and fixed school characteristics) and the concept of organisational routines are used. Semistructured interviews were held with 21 teachers and 15 school leaders from the 14 schools who participated in the project. Findings show schools reported nine school factors that influenced their (dis)continuation of lesson study after the project: five features of employment (part-time appointment, turnover, (un)planned leave of absence, work location and beginning teachers), three malleable processes (policies on improvement, scheduling and school finances), and one fixed school characteristic (school size). School factors were reported to constrain schools from making lesson study a repeated practice in the school, performing its core features, and ensuring collective attendance. Two narrative portraits revealed that the simultaneous occurrence of school factors made continuing with lesson study especially complex and limited schools' ability to move beyond shortened and simplified initiatives to more rich and meaningful professional development.