This study aims to understand how buyer–seller relationship, competitive environment and guanxi affect Chinese manufacturers’ decision to implement Green Supply Chain Collaboration (GSCC). We also examine whether guanxi is able to mediate the buyer–seller relationship and GSCC implementation. Data collected from 222 Chinese manufacturing organizations were analyzed using the partial least squares method of structural equation modeling. The result shows that buyer–seller relationship influences Green Supply Chain Collaboration through asset specificity, volume uncertainty, transaction frequency and competitive environment. The results also showed support for our hypotheses that guanxi mediates the effect of asset specificity, volume uncertainty and environmental competition on GSCC.