Amado, NéliaDomingos, AntónioJones, Keith2017-04-072017-04-072016-070268-3679AUT: NAM01269;http://hdl.handle.net/10400.1/9437This paper introduces a special journal issue presenting selected papers from the 12th International Conference on Technology in Mathematics Teaching (ICTMT12), hosted by the Faculty of Sciences and Technology of the University of Algarve, in the city of Faro, from 24-27 June 2015. With the overall theme of re-visioning teaching and learning with technology in mathematics, the papers in the special journal issue offer insights into the range of possibilities for the integration of technology in the teaching and learning of mathematics at the upper secondary and tertiary levels of education (including in teacher education). The insights cover teachers' knowledge for teaching mathematics with technology (KTMT), an adaptation of the technological pedagogical content knowledge (TPACK) theoretical framework, an ‘embodied’ approach to the convergence of numerical sequences using GeoGebra, and examples of how GeoGebra can be used to explore complex functions. Such insights are an important part of re-visioning teaching and learning mathematics with technology.engjournal article10.1093/teamat/hrw004