This paper builds a model of cumulative growth to examine the dynamic interdependent relationship between Information and Communication Technology (ICT) investment and economic growth for a sample of 29 countries in the 1990s. We confirm the following facts: First, there is a positive correlation between ICT investment and economic growth. Second, non-ICT investment has as much influence on the growth gap as ICT investment. Third, those countries with a solid economic infrastructure and open trade regime experience more active ICT investments. Fourth, those countries with a comparatively lower productivity level can reduce the gap using knowledge spillovers from more advanced countries. Fifth, reinforcement of patent rights has a positive influence on economic growth by stimulating the accumulation of ICT capital. Finally, ICT investment does not have a strong interdependent relationship with economic growth, while non-ICT investment has a cumulative causal relationship with economic growth and plays a key role in the process of widening the growth gap.