We　address　the　dynamics　of　a　surfactant-laden　droplet　on　a　solid　surface　in　simple　shear　flow　numerically.　Our　analysis　uses　the　front-tracking　method　to　take　surfactant　transport　into　account.　The　interfacial　tension　and　the　slip　coefficient,　both　of　which　depend　heavily　on　the　surfactant　concentration,　are　fully　integrated　into　the　generalized　Navier　boundary　condition　to　model　the　moving　contact　lines.　Accurate　prediction　of　droplet　motion　indicates　that　the　surfactant　can　change　droplet　behavior　drastically.　Surfactant-induced　effects,　such　as　interfacial　tension　reduction,　the　Marangoni　stress,　and　wettability　alternation,　are　investigated　for　various　capillary　numbers,　surface　wettabilities,　elasticity　numbers,　and　surface　Péclet　numbers.　Deformation　and　motion　of　a　sliding　droplet　are　enhanced　by　the　Marangoni　effect,　which　is　associated　with　an　interfacial　tension　gradient.　When　the　capillary　number　reaches　a　critical　value,　the　sliding-to-detachment　and　detachment-to-pinch-off　transitions　occur.　Both　transitions　can　be　triggered　and　accelerated　by　a　surfactant,　especially　when　convection　is　dominant.　As　a　result,　the　critical　capillary　number　decreases,　but　exhibits　a　non-monotonic　relationship　with　the　elasticity　number　and　Péclet　number.　The　mechanisms　that　underlie　the　effect　of　Marangoni　stress　are　discussed　by　analyzing　the　distributions　of　the　surfactant　concentration　and　the　hydrodynamic　forces　exerted　on　the　droplet.　Accumulation　of　surfactants　near　the　receding　contact　line　reverses　the　local　concentration　gradient,　attempts　to　change　its　direction　along　the　interface,　and　delays　droplet　detachment.　Furthermore,　the　strong　surfactant　dilution　reduces　both　the　surfactant　concentration　and　the　interfacial　tension　gradient,　and　thereby　increasing　the　critical　value　for　droplet　pinch-off.　©　2022　Elsevier　B.V.