This study aims to revisit the concept of the threshold in Le Corbusier’s residential architecture by examining how the physical boundary is transformed into a mediating and experiential space. The central research question is that, in Le Corbusier’s works, the threshold no longer functions merely as a doorway or a rigid boundary separating interior and exterior. Rather, it emerges as a spatial-perceptual process characterized by gradual transition, multilayered organization, and temporality. The research adopts a qualitative approach based on logical reasoning. Four of Le Corbusier’s representative residential projects—Maison Curutchet, Villa Cook, Villa Savoye, and Villa Shodhan—were selected as case studies. Each project was analyzed according to six principal threshold components: spatial mediation, movement sequence, spatial depth, modulation of light and shadow, visual suspension, and embodied perception. The findings indicate that Le Corbusier transforms rigid boundaries into mediating and experiential spaces through architectural strategies such as ramps, pilotis, recessed façades, semi-open terraces, deep brise-soleil, and carefully framed views. The results further demonstrate that the threshold in his architecture is not an isolated architectural element but an integral part of the broader spatial and perceptual organization of the building. By proposing an analytical framework for interpreting thresholds in modern architecture, this study contributes to a deeper theoretical understanding of Le Corbusier’s work and offers insights that may inform the reconsideration of threshold design in contemporary residential architecture.