This paper investigates the impact of boundary-spanning search on innovation performance, with knowledge recombination as the underlying mechanism. It also explores the contingent effect of in house training of employees by considering not invented here syndrome derived from attitude theory, and examines communication investment as a second-order moderator. We test the hypotheses based on a sample of 184 Hong Kong manufacturing firms. The results show that boundary-spanning search is positively related to innovation performance, which is negatively moderated by in house training of employees. Moreover, communication investment has a suppressing effect on the moderating role of in house training of employees. This paper highlights the not invented here syndrome and its mechanism of attitude theory to examine the contingent effects, providing insights for managers to balance among in house training of employees, communication investment, and boundary-spanning search to enhance innovation performance.