The 2017 New Jersey General Assembly elections were held on November 7, 2017, to elect members to all 80 seats of the New Jersey General Assembly. Prior to the elections, Democrats held a 52–28 majority in the lower house. Overall, the Democrats increased their majority by 2 to a super-majority at 54–26, due to holding all their seats as well as picking up open seats in District 2 and District 16. This tied Democrats for their largest majority since 1979.

The 2017 New Jersey State Senate elections were held on November 7, 2017, to elect Senators for all 40 legislative districts across New Jersey. These elections coincided with the election of Governor Phil Murphy. The winners of this election serve in the 218th New Jersey Legislature, with seats apportioned based on the 2010 United States census. The Democratic Party grew its majority in the Senate, with incumbent Senate President Steve Sweeney re-elected to the top leadership post. Republican Thomas Kean, Jr. continued to lead his party as Minority Leader. This was the first state Senate election cycle in 10 years where any party flipped a Senate seat.