TRACT This study develops a framework for analyzing student comments in Wikis of group writing to inform learning assessment. It first drew on the literature to develop a framework consisting of three modules measuring student interaction, meaning construction and thinking development in the writing process. Inservice teachers were interviewed to ensure framework practicality and inform subsequent refinement. A sample of 1,482 Wiki page comments was collected from 48 groups of secondary school students in Hong Kong to test the developed framework. Statistical analyses and association rule mining were conducted to the coded data to explore the relations among coding categories. This study aims to raise the attention on page comments in the analysis of student activities in Wiki and provided empirical evidence on category relations, which will be instructive for further research and practice in Wiki-supported learning.