This qualitative case study involves a high school science teacher with a special education background in an urban school in the English School District of Newfoundland and Labrador. Conceptualized within the theoretical framework of Universal Design for Learning (UDL), this study examined the teacher's instructional practices and the tensions she experienced in the adoption of inclusive science pedagogy. This is a descriptive study that used different data collection methods, including interviews, observations, and documents. Data were analyzed inductively with MAXQDA software using constant comparative analysis. Findings showed that the teacher's instructional practices in the implementation of inclusive pedagogy focused on creating multiple means to (a) engage diverse students, (b) represent the science curriculum, and (c) enable diverse students to express and communicate their understanding of science. However, several tensions were identified, which impeded the teacher's effort in the implementation of inclusive science pedagogy. These tensions include inadequate instructional resource teachers, inflexible science curriculum, overreliance on standardized testing, and inadequate professional learning. The paper concludes with implications for science teachers and pre-service teachers' education, with recommendations on future research direction.