This paper examines the concept of constructive alignment in respect of science education. The concept is placed in the context of its two contributory components--constructivism and instructional alignment. The former has a well-established body of critical literature that highlights the challenges of constructivism for both science and science education. The instructional alignment component is a long-standing behaviourist approach to curriculum planning. Linking the two components in constructive alignment purports to offer "a theory of learning that is broad-based and empirically sound, and that easily translates into practice" married to "an aligned design for teaching". This approach appears to have the uncritical support of key organisations in UK Higher Education. However, we suggest that linking two contested theories is unlikely to lead to generally sound advice on either curriculum design or approaches to science teaching.