Increasingly, digital technologies are being utilised to provide opportunities for teacher professional learning (PL) in fully online, blended and face-to-face environments. Videos have been used extensively across the three modes of delivery but there appears little research on the conceptual framing underpinning their development. This article describes and analyses a research-informed instructional design approach taken to develop an online resource to support teacher PL. The approach utilised a conceptual framework consisting of an audit framework and model of numeracy for the twenty-first century to guide an audit of existing resources, gap analysis and production of an online resource. The purpose of the resource audit was to establish how existing resources support teachers' understanding and enactment of numeracy across the curriculum. Gaps where teachers might benefit from new resources were identified through the resource audit and subsequent interviews with stakeholders. The conceptual framework was employed to inform the development of a suite of six videos: one to enhance teachers' understanding of the meaning of numeracy; four to demonstrate teachers' embedding of numeracy in particular subjects; and one that captured a collaborative planning session. This article adds to new knowledge within the discipline by providing insight into instructional design processes that could be employed in other contexts related to the identification and/or development of resources for online PL that target specific learning needs of teachers.