Nanofiltration (NF) is a de novo class of membrane filtrations with unique properties ranging from ultrafiltration to reverse osmosis. Thanks to their high removal performance, NF membranes have gained increasing attention from both academia and industry for various applications, especially in water and wastewater treatment and desalination. However, the NF process still requires further improvement in terms of selectivity, separation efficiency, membrane fabrication, operation requirements, and sustainability.