Boston’s 49th mayoral race will tighten this week as voters narrow the field to two candidates in the preliminary elections Tuesday.

A poll taken in June by the Suffolk University Political Research Center showed incumbent Mayor Martin J. Walsh with a lead of 54 percent. Walsh’s toughest competition comes from Tito Jackson, a District 7 councilman, who is second in the polls. Jackson’s serious intention to increase affordable housing, a key consideration for many voters, could help him gain support. Joseph Wiley and Robert “Bob” Cappucci are also running, but have only 5 percent of the vote between them.

Martin J. Walsh

Walsh, 50, was born and raised in Boston and served as a Massachusetts House representative for 17 years before running for mayor.

“I am running for reelection so Boston can continue to be a place where every family can thrive and every child can reach their dreams,” Walsh said in a Sept. 13 statement.

Walsh has accumulated more than $2 million in campaign funds for this coming race, significantly more than any of the other candidates, according to his campaign finance report filed in the Massachusetts Office of Campaign and Political Finance.

Walsh’s first term followed the late Thomas Menino’s 2014 step-down from office because of an extensive battle with cancer. During his term, Walsh helped extend MBTA hours and attempted to bring the 2024 Olympics to Boston. He has held a solid lead in preliminary polls throughout the summer.

“We are ready to build on this progress,”  Walsh said in the statement. “There is more work to do, but we are on the right track.”

Walsh also stood against President Donald J. Trump’s threat to pull federal funding from sanctuary cities.

“If people want to live here, they’ll live here,” Walsh said in a January speech. “They can use my office. They can use any office in this building.”

In June 2016, the U.S. District Court indicted two of Walsh’s aides for extortion and conspiracy after they supposedly pressured the Boston Calling music festival into hiring union workers, staining Walsh’s first term.

However, Walsh remains focused on Boston’s top issues. He is optimistic about his ability to help the housing market.

“We’ve built affordable housing at a record pace,” Walsh said in the Sept. 13 statement. “Our plan to create 53,000 units of housing by 2030 is off to a fast start, with more than 21,000 new homes either built or in construction.”

Tito Jackson

Jackson has been a harsh critic of Walsh’s efforts to create affordable housing throughout his current term.

According to a poll conducted by the Boston Globe/Suffolk University, 70.8 percent of voters consider Boston housing unaffordable, meaning that a majority of Boston residents aren’t satisfied with Boston housing.

A spokesperson for the Jackson campaign also said Jackson wants to tackle the growing gentrification in Boston, as he feels the construction of new high-rises and luxury condominiums are making it increasingly difficult for Roxbury residents to afford to live in their historical neighborhood.

Jackson’s spokesperson said Jackson wants to lessen the power of the mayorship, as he believes this will bring about more democracy in Boston. He also hopes to have a scandal-free government, citing the current administration’s two indicted aides still on the payroll.

Robert Cappucci and Joseph Wiley

Cappucci received the third most votes in Suffolk University’s polling, though significantly behind the leading candidates at 4 percent.

Cappucci, 72, served in the Navy and was a police officer in the Boston Police Department. Cappucci holds some unique positions in the race, as the only pro-life candidate.

Cappucci is a real estate project manager at Massaro Development and was born and raised in East Boston. Cappucci is primarily focused on local issues that directly affect citizens’ day to day lives. According to his website, Cappucci wants to give the city back to its people and protect the veterans and elderly of Boston, ensuring that they have quality lives.

Cappucci was not immediately available for a comment.

Wiley accumulated less than 2 percent of the vote in Suffolk University’s June polling, slightly less than Cappucci.

Wiley, 68, is a customer service representative from East Boston and is finally on the ballot after years of failing to accumulate the prerequisite 3,000 constituent signatures. Wiley ultimately used his personal savings to hire a professional to collect the signatures last year.

According to his website, Wiley wants to decrease homelessness and build more affordable housing, which he believes will help the 1,300 homeless families living in Boston.

Wiley did not respond to multiple requests for comment.

Voter registration for the preliminary election is currently closed, but registration for the general election can be found here.