This PRIDE project contains raw and processed LC-MS/MS data generated from immunoprecipitation–mass spectrometry (IP-MS) experiments designed to identify PPARα-associated proteins in mouse bone marrow-derived macrophages (BMDMs). In this study, His-tagged PPARα was overexpressed in BMDMs and immunoprecipitated using anti-His magnetic beads, followed by proteolytic digestion of the immunoprecipitated protein complexes and LC-MS/MS analysis. Peptides were separated using an Easy nLC 1200 nano-flow liquid chromatography system and analyzed on a Q Exactive HF-X mass spectrometer operated in data-dependent acquisition mode. Raw MS data were searched using MaxQuant (version 2.4.14.0). This dataset was generated as part of a study investigating the mechanism by which fibrin stiffness regulates macrophage polarization and metabolic reprogramming in metabolic dysfunction-associated steatohepatitis (MASH).