This research explores how a supplier's trust (goodwill and integrity) and a long-term orientation affect two types of customer involvement: 1) customer as an information source (CIS); 2) customer as a co-developer (CIC). The relationship between CIS and CIC with new product performance is also examined. Hypotheses were tested using survey data gathered from 155 manufacturing firms in China and were analysed using partial least squares regression. Long-term orientation is positively related to using both CIS and CIC, but trust is only related to using CIS. We expected that the relationships of trust and long-term orientation would be stronger when CIC was used compared to CIS, but this was not supported. Further, CIS, but not CIC, is positively related to product performance. Future research should explore development processes, capabilities, and product characteristics better to understand the use of and outcomes from CIC.