Heterojunction photocatalysts BiOBr/BiVO₄ were in situ synthesized through acid etching coupled with a hydrothermal process, and the optimized BiOBr/BiVO₄ ratio was tuned to explore their visible-light photocatalytic activity for MB degradation. Remarkably, BiOBr/BiVO₄ composites exhibited higher visible-light photocatalytic ability compared with single BiVO₄ and BiOBr alone. The charge-separation process was interpreted based on the energy band structure. The heterojunction formed between BiVO₄ and BiOBr, that effectively promotes the separation of photo-induced electrons and holes, is responsible for the improved photocatalytic activity.