Tests convey messages about what to teach and how to assess. Both of these dimensions may either broaden or become more uniform and narrow as a consequence of high-stakes testing. This study aimed to investigate how Swedish science teachers were influenced by national, high-stakes testing in science, specifically focusing on instances where teachers' pedagogical practices were broadened and/or narrowed. The research design is qualitative thematic analysis of focus group data, from group discussions with Swedish science teachers. The total sample consists of six teachers, who participated in 12 focus group discussion during three consecutive years. Findings suggest that the national tests influence teachers' pedagogical practice by being used as a substitute for the national curriculum. Since the teachers do not want their students to fail the tests, they implement new content that is introduced by the tests and thereby broaden their existing practice. However, when this new content is not seen as a legitimate part of teachers' established teaching traditions, the interpretation and implementation of this content may replicate the operationalisations made by the test developers, even though these operationalisations are restricted by demands for standardisation and reliable scoring. Consequently, the tests simultaneously broaden and narrow teachers' pedagogical practices.