This study examines differences between users and nonusers of information communication technologies (ICTs) within the pre-incident planning processes for domestic terrorist movements operating within the United States. In addition, this study is the first quantitative exploration of the prevalence, types, and purposes of ICT use within terrorist movements, specifically environmental, far-right, and Islamic extremist movements. Using“officially designated” federal terrorism investigations from the American Terrorism Study (ATS), we analyzed extracted evidence of ICT usage among individuals (n =331) engaged in the pre-incident planning processes as members of terrorist movements between 1995-2011. While we find significant differences in terrorist ICT use across terrorist movements, our findings suggest that demographics are not a strong predictor of usage. We find the highest prevalence of usage among Islamic movements. However, evidence of online radicalization or recruitment was found predominantly among environmental movements. We conclude with a discussion of these findings and their implications for counterterrorism policy.