This paper presents a simple R&D-based growth model of the "technological divide," in which learning-by-doing (investing) in R&D and a threshold level of technological knowledge jointly determine the pattern of economic growth. Specifically, the model generates differences in the growth pattern primarily by modifying the underlying parameters that govern the evolution of economy-wide technological competence or dynamic R&D productivity. The technological divide arises at the threshold level of technological knowledge, which is largely affected by the quality of socio-technological infrastructure. Government policies aimed at enhancing the quality of socio-technological infrastructure can help countries escape from the "technology divide" trap by lowering the knowledge threshold. While the model preserves the spirit of the R&D-based endogenous growth model in the sense of its policy effects and the endogenous evolution of technological competence, the model does not need to reach the scale effect directly, where an increase in the size of an economy generates more rapid growth.