The need to improve the quality of higher education has fostered an interest in technology tools to support effective design for teaching and learning. Over the past decade this interest has led to the development of tools to support the creation of online learning experiences, specifications to underpin design systems, and repositories to share examples. Despite this significant activity, there remain unanswered questions about what shapes university teachers' design decisions and how tools can best support their design processes. This paper presents findings from a study of university teachers'; design practices that identified teachers' perceptions of student characteristics, their own beliefs and experiences, and contextual factors as key influences on design decisions. The findings extend our understanding of activities fundamental to higher education teaching and inform thinking about design support tools.