Cancer-associated fibroblasts (CAFs) are increasingly recognized as an important component of the brain metastasis tumour microenvironment; however, their proteomic phenotype remains poorly characterized. This dataset contains mass spectrometry-based proteomic profiles of primary human brain metastasis-associated fibroblasts (BrM-CAFs) isolated from lung cancer brain metastases (L-BrM-CAF, n = 3) and control, non-tumorous subgalear fibroblasts (Subgalear-NF, n = 3). Whole-cell lysates were analyzed using data-independent acquisition (DIA) mass spectrometry, supported by a project-specific spectral library generated from data-dependent acquisition (DDA) measurements. The dataset was generated to characterize the molecular phenotype of BrM-CAFs and to investigate protein-level alterations associated with stromal activation, extracellular matrix remodelling, and tumour–stroma interactions. The data provide a resource for studies of the brain metastasis microenvironment and CAF biology.