Language is a key part of learning science. Many students for whom English is an additional language or dialect (EAL) encounter difficulties learning science because of their lack of proficiency in English (McCallum & Miller, 2013). These students make up approximately a quarter of the population of many Australian schools (ACARA, 2020). This article discusses a purposeful collaboration between science and EAL teachers focusing on language development in science lessons. This article synthesises the insights of science and EAL teachers who participated in a professional development program based on collaborative curriculum design. The curriculum redesign is not straightforward; it requires an in-depth understanding of the subject matter and how students learn science and language. However, provided that they are given the time and the autonomy to adjust the school program to meet the needs of their students, this study demonstrated how the joint expertise of science and language teachers could lead to substantively changing classroom practices to enhance the learning of EAL students.