This study aims to examine the impact of Information and Communication Technology (ICT) on economic growth. Specifically, the author employs Principal Component Analysis (PCA) to calculate the ICT index based on four indicators in the ICT sector for Southeast Asian countries during the period from 1990 to 2022, using Bayesian methods. The findings indicate that a productivity paradox has emerged in these countries during the study period, showing that ICT has a negative effect on economic growth. However, an interesting discovery is that implementing reasonable public expenditure policies in the ICT sector can lead to a positive impact on economic growth, with a probability of effectiveness reaching 99%. Furthermore, the research analyzes the probability of ICT’s impact on each country and finds that each nation, due to its unique socio-economic characteristics, experiences different effects on economic growth. This suggests that specific policy implications should be developed for each country.