This paper offers a framework, an extension of Valsiner's "zone theory", for the analysis of joint student-teacher development over a series of technology-based mathematics lessons. The framework is suitable for developing research studies over a moderately long period of time and considers interrelated student-teacher development as well as the influence of "significant others" on teacher development. After a short introduction, the paper sketches the need for a framework that can capture student and teacher development over technology-based mathematics lessons. It then outlines Valsiner's zone theory and the extension of this theory. The paper ends with a consideration of theoretical, methodological and practical issues in researching innovative mathematics classroom work with technology.