The 25-year-old, who appeared in 14 of the club's 17 matches in 2020-2021, is back onboard for another assault at the National League North title.
He won the division with Stockport County in 2019 and arrived in Lincolnshire after a spell with AFC Fylde.
United manager Craig Elliott said: "I worked very hard last season to get Scott to come to Boston United, so I am therefore delighted he has agreed to sign for another year.
"He was getting back to his very best with every game he played – and you could see his confidence and match fitness improving all of the time.
"As a former champion of this league with Stockport County, his experience will be vital as he knows exactly what it takes to win the division with a big club."