We report on the first demonstration of the CMOS-compatible integration of high-quality InGaAs on insulator (InGaAs-OI) on Si substrates by a novel concept named Confined Epitaxial Lateral Overgrowth (CELO). This method, based on selective epitaxy, only requires the use of standard large-area silicon substrates and typical CMOS processes. It enables the fabrication of InGaAs-OI starting from both bulk and SOI Si wafers. The InGaAs epitaxial structures are characterized by a very low defectivity, and can fulfill the requirements of both ultra-thin-body and fins-based advanced CMOS nodes. Gate-first self-aligned FinFETs (100-nm-long gate, 50-nm-wide fins and 250-nm-wide plug-contacts) with excellent electrical characteristics comparable to start-of-the-art InGaAs MOSFETs on Si are demonstrated, highlighting that this new concept has significant potential to enable introduction of high-mobility channel materials in high-volume manufacturing of advanced CMOS nodes.