This paper, using Thailand as a case study, aims at understanding the national innovation system (NIS) in developing countries which are less successful in technological catching-up. In contrast to developed countries, the development level of Thailand’s NIS does not link to its economic structural development level. As Thailand moves from agricultural to an increasingly industrial economy, its NIS remains weak and fragmented. The mismatch between the two affected Thailand’s competitiveness and partially contributed to the recent economic crisis.