This dataset contains supplementary data for the ESAFORM 2022 conference paper entitled: 'On the effect of release agent and heating time on tool-ply friction of thermoplastic composite in melt'. The dataset consists of inter-ply friction tests on UD C/PEKK in melt using a friction tester located at the University of Twente to simulate the response during actual hot press forming of thermoplastic matrix composites. Several conditions (different sliding velocities, temperatures, and normal pressures) are measured with and without release agent applied in an effort to investigate the effect on the transient tool-ply friction response. Furthermore, the effect of the heating time on the subsequent tool-ply friction is measured, for which also ply-ply friction experiments are conducted. The experimental procedure is described and an overview of the used specimens with their test conditions is provided. Matlab scripts are included to replot the figures as shown in the mentioned conference paper.