This study investigated the impact of fermentation with probiotic strain L. plantarum 299v on the techno-functional charac- teristics and selected antinutritional factors (ANFs) of lentil flour. Samples were collected at 6 (F6), 12 (F12), and 24 h (F24) of fermentation and compared to uninoculated flour (control). Comprehensive analyses included quantification of bioactive compounds and antioxidant capacity (in vitro) via spectrophotometric assays. Condensed tannins, phytic acid, and trypsin inhibitor activities were also measured. The influence of fermentation on proximate composition and techno-functional properties was evaluated. Thermal and pasting properties were also assessed. Results indicated that fermentation significantly increased foaming stability and decreased emulsification stability compared to the control. No significant changes (p > 0.05) were observed in oil and water holding capacities, emulsifying activity, foaming capacity, pasting temperature, or pasting parameters. Extended fermentation (F12, F24) led to reduced antioxidant, phenolic, and flavonoid contents. Notably, among fermented samples, the highest antioxidant activity, with a reducing power of 3.70 ± 0.10 mg AAE/g d.w. and 79.23 ± 2.08% DPPH inhibition was noted for F6. All reduced phytic acid, tannins, and trypsin inhibitor levels, alongside an increase in insoluble dietary fiber, most pronounced in F24. These findings underscore the potential of applied fermentation as an effec- tive bioprocessing strategy to significantly reduce ANFs, while maintaining or enhancing the techno-functional integrity of lentil flour. This approach offers a promising tool for improving the nutritional quality and functional performance of legume-based ingredients in food applications.