This study compares knowledge sourcing strategies (KSS) employed, and innovation performed, by manufacturing firms in high-income (HI) and middle-income (MI) countries using global innovation data derived from the UNESCO Institute for Statistics (UIS). KSS consists of both closed innovation (internal R&D) and open innovation. This study provides new empirical evidence at country level on the link between KSS and innovation across manufacturing firms in HI and MI countries. In the case of R&D activities, evidence from this study reveals that there is a significant different between manufacturing firms in HI and MI countries. Manufacturing firms in the former group of country is significantly performing internal R&D greater than in the latter group of country. Within HI and MI economies, practicing open innovation in isolation alone does not lead to high level of innovation output.  Evidence from HI countries shows that other factors such as R&D activities and R& investment that is also supported by IPRs are correlated to innovation. The key contribution of this study is to provide new empirical evidence on the comparison of KSS – innovation association in the context HI and MI countries that to date is relatively few. Relevant theoretical and practical implication are drawn from this study.This study compares knowledge sourcing strategies (KSS) employed, and innovation performed, by manufacturing firms in high-income (HI) and middle-income (MI) countries using global innovation data derived from the UNESCO Institute for Statistics (UIS). KSS consists of both closed innovation (internal R&D) and open innovation. This study provides new empirical evidence at country level on the link between KSS and innovation across manufacturing firms in HI and MI countries. In the case of R&D activities, evidence from this study reveals that there is a significant different between manufacturing firms in HI and MI countries. Manufacturing firms in the former group of country is significantly performing internal R&D greater than in the latter group of country. Within HI and MI economies, practicing open innovation in isolation alone does not lead to high level of innovation output.  Evidence from HI countries shows that other factors such as R&D activities and R& investment that is also supported by IPRs are correlated to innovation. The key contribution of this study is to provide new empirical evidence on the comparison of KSS – innovation association in the context HI and MI countries that to date is relatively few. Relevant theoretical and practical implication are drawn from this study.