There has been ample research on brand value co-creation (BVCC), but majorly it involved only one stakeholder (i.e., customers) as the source of co-creation. This paper aims to study employees' brand citizenship behaviors (EBCB) with retailers' brand value co-creation behaviors with a mediation mechanism of brand attachment in the FMCG sector. Scales were adapted from previous studies to measure EBCB, brand attachment, retailer-led feedback, retailer-led advocacy, and retailer-led helping. Data were collected through selfadministered questionnaires, and PLS-SEM was used to analyze a sample of 189 salespersons and retailers. The findings support the complimentary partial mediation role of brand attachment in fostering retailers' BVCC behaviors by EBCB. This study offers comprehensive insights into employees' behaviors in cultivating retailers' co-creation behaviors. Firms and marketers may benefit by focusing on the behaviors of their employees, especially sales employees who frequently visit retail stores.