Colleen Young was elected to replace former cabinet minister Tim McMillan, who resigned to become president of the Canadian Association of Petroleum Producers.
Premier Brad Wall tweeted his congratulations to Young and said the "big win" was good news for his government.
"Voters sent message: on the right track ... still more work to do."
Young had taken a leave of absence as chairwoman of the Lloydminster Public School Board, where she has been a trustee for 20 years. She also currently sits on the University of Saskatchewan senate.
Young and her husband, Kim, have eight children and have lived in the constituency for the past 28 years.
"I am honoured to be able to represent this constituency within the government of Saskatchewan," Young told radio station CKSA. "I'm looking forward to the work I will do on their behalf."
She said there's a lot that needs to be done.
"There's lots to learn, you know, learning the procedures and the rules within the house. Getting to know the people I'll be working with. Getting my office set up and getting those things in place, including making sure I have a constituency office here in Lloydminster that the people can come to when they need to talk."
The result was very close to McMillan's last win; with all 45 polls reporting, Young had 64 per cent of the vote compared to 29 per cent for the NDP's Wayne Byers. In 2011, McMillan bested Byers by a margin of 66 per cent to 29 per cent.
Liberal Leader Darrin Lamoureux managed to get only three per cent of the vote, the same as Randall Edge of the P.C. Party of Saskatchewan. Luke Bonsan of the Green Party brought up the rear with two per cent.
McMillan, who had represented the constituency since November 2007, had been minister in charge of rural and remote health and was replaced in the portfolio by Greg Ottenbreit.
Lloydminster is a community of nearly 28,000 people that straddles the boundary of Saskatchewan and Alberta. Only the approximately 10,000 voters who live on the Saskatchewan side of the city were eligible to vote and of those, 2,793 cast ballots.
The Saskatchewan Party now holds 49 seats in the legislature, while the NDP holds nine.