The article reviews the recent progress and applications of organic solvent nanofiltration (OSN) in the pharmaceutical industry. OSN offers significant advantages over conventional separation technologies such as distillation and chromatography, including low energy consumption, minimal solid waste, and ease of scale-up. The review covers the concentration and purification of active pharmaceutical ingredients (APIs), homogeneous catalyst recovery, solvent exchange and recovery, and OSN-assisted peptide/oligonucleotide synthesis. It also discusses the challenges and future perspectives of membrane technology in pharmaceutical applications. Key topics include the fundamentals of OSN, membrane performance characterization, separation mechanisms, and the development of different types of OSN membranes. The article highlights the potential of OSN in improving sustainability and energy efficiency in pharmaceutical manufacturing.The article reviews the recent progress and applications of organic solvent nanofiltration (OSN) in the pharmaceutical industry. OSN offers significant advantages over conventional separation technologies such as distillation and chromatography, including low energy consumption, minimal solid waste, and ease of scale-up. The review covers the concentration and purification of active pharmaceutical ingredients (APIs), homogeneous catalyst recovery, solvent exchange and recovery, and OSN-assisted peptide/oligonucleotide synthesis. It also discusses the challenges and future perspectives of membrane technology in pharmaceutical applications. Key topics include the fundamentals of OSN, membrane performance characterization, separation mechanisms, and the development of different types of OSN membranes. The article highlights the potential of OSN in improving sustainability and energy efficiency in pharmaceutical manufacturing.