This research was conducted to investigate the antecedents directly and positively affecting organization’s word-of-mouth towards professional service, primarily in the context of B2B professional general insurance services in Vietnam. The empirical results of this research indicated that five out of seven factors, namely interpersonal skills, premium, technical skills, reputation and risk coverage had both significantly positive direct and indirect effects on organization’s word-of-mouth with the mediation role of organization’s perceived service quality. Based on the empirical results, it is suggested that insurers should improve organization’s perceived service quality, and thereby enhance their word-of-mouth behavior.