When technologies like GeoGebra are implemented in mathematics lessons, the focus should be on learners and their learning processes rather than on technologies. Student-centeredness is a core characteristic of flipped classroom approaches. Recent further developments of flipped classroom approaches aim to foster learning through inquiry in flipped scenarios. In this study, we are particularly focusing on the 5E-based flipped classroom approach. We investigated how secondary mathematics teachers planned to use GeoGebra in their written lesson plans for 5E based flipped classroom scenarios. Using coding procedures related to qualitative content analysis, we conducted a document analysis on 24 written lesson plans. Findings indicate, for instance, that participants not only planned to use dynamic GeoGebra materials in exploratory phases during class. Some teachers also intended to use a screencast demonstrating the GeoGebra applet in a pre out-of-class phase to engage students in the inquiry process or for consolidation after exploration.