PurposeThis study examines how three psychological factors (i.e. perceived experience quality, perceived similarity and client participation) that impact client evaluations of their recent audit experiences influence client satisfaction and trustworthiness, which, in turn, affect advocacy in an small- and medium-sized enterprise (SME) context. Furthermore, the study investigates whether the influence of the three psychological factors on client satisfaction and trustworthiness is contingent on client expertise.Design/methodology/approachThe sample consisted of 744 SME executives from the following four regions: central, northern, eastern and southern Thailand. Data were collected using a survey questionnaire. Confirmatory factor analysis was conducted to ensure the reliability and validity of the scale before structural equation modeling was applied to analyze the data.FindingsThe results showed significant positive effects of the three psychological factors (perceived experience quality, perceived similarity and client participation) on client satisfaction and perceived trustworthiness. The moderating role of client expertise on the relationships is also found. More specifically, client expertise positively moderated the connections between experience quality and satisfaction, experience quality and trustworthiness and client participation and trustworthiness. Conversely, client expertise negatively moderated the similarity–satisfaction and similarity–trustworthiness relationships.Originality/valueThis study contributes to the audit literature by examining the role of psychological factor that impacts client satisfaction and perceived trustworthiness in the SME context. Moreover, the moderating role of client expertise is examined for the first time, providing new insights into the boundary condition of the relationship.