Worker voice tools can support multinational companies to monitor social compliance within complex multi‐tier apparel supply chains. This study presents findings from an adaptation of a worker voice tool that contacted 11,555 workers in two informal ‘Ready‐made Garment’ (RMG) production hubs in Bangladesh. Results indicate a high level of child labour, particularly among boys, and present characteristics of exploitative working conditions. The authors also share challenges in facilitating support services for identified child labourers. This study informs multi‐sectoral strategies for business adherence to sustainable supply chain management, and government commitment to Sustainable Development Goal (SDG) 8 for Decent Work and Economic Growth.