Abstract The new mathematics curriculum for senior high school in Ghana encourages teachers to make use of the calculator and the computer for problem solving and investigations of real life situations. The goal is to help students acquire the habit of analytical thinking and the capacity to apply knowledge in solving practical problems. As a result, the government and other institutions have invested huge sums of money in procurement of computers and establishment of computer labs in most senior high schools; however, there still exists a gap between this new concept of teaching with ICT as specified in curriculum and policy documents and the use of ICT in practice. Important questions such as “what can teachers do with computers to extend their instructional methods and improve students’ outcomes?” remain unanswered. This chapter describes three iterations of an instructional course for pre-service mathematics teachers in Ghana aimed at addressing this type of question. The course design was based on Technological Pedagogical Content Knowledge as a conceptual framework for the course content and Learning Technology by Design as the course method. This chapter shows how evaluations informed the design of the successive iterations, and proposes a set of guidelines for design of similar courses in similar contexts.