Purpose: This paper aims to focus on the effects of human capital composition, innovation portfolio and size on manufacturing firms’ performance. Moreover, it seeks to empirically identify the levels of education that are significant in labour productivity. Design/methodology/approach: The resource-based view (RBV) theory is applied using data gathered from the National Innovation Survey in the Manufacturing Industries of Peru. Using the ordinary least squares method on a sample of 584 Peruvian manufacturing firms, the effects on firm performance of two subsamples according to innovation portfolio and firm size are determined. Findings: The direct effects of human capital composition on productivity show that the higher the workers’ educational level, the higher the productivity. However, if this relationship is analysed in terms of the innovation portfolio, the authors find that labour productivity in companies with product–service innovation is greater (i.e. more significant) than in traditional manufacturing firms with only product innovations. Similarly, if this relationship is compared in terms of company, the authors find that large companies are more significant than small and medium-sized enterprises. Practical implications: The study furthers the understanding of how the relationship between human capital composition, innovation portfolio and size of manufacturing firms positively affects labour productivity. Hence, it can help managers to craft their innovation portfolio according to the educational level of their human capital. This could require that not only human resource management innovates, but also that strategic partnerships be developed with educational establishments to boost training towards product–service innovation. Originality/value: This study’s results provide confirmation that the configuration of human resources, innovation portfolio and size plays a significant role on manufacturing firms’ performance, particularly in the context of developing countries.