Robinson took over from Mark McGhee in March 2017 and has led the Steelmen to both the Betfred and Scottish Cup finals during his time in charge.
Well chairman Jim McMahon told the club website: "They have created a true culture of hard work and continual improvement, an ethic that is evident in everyone they come into contact with.
“We are excited to work closely with them as they continue their efforts for the betterment of Motherwell Football Club going forward.”
