STAR voting is an electoral system for single-seat elections. The name (an allusion to star ratings) stands for "Score Then Automatic Runoff", referring to the fact that this system is a combination of score voting, to pick two finalists with the highest total scores, followed by an "automatic runoff" in which the finalist who is preferred on more ballots wins. It is a type of cardinal voting electoral system.

In STAR, voters are given a score ballot (or ratings ballot) on which each voter scores candidates with a number from 0 up to 5, with 0 representing "worst" and 5 representing "best". The scores for each candidate are then summed, and the two highest-scored candidates are selected as finalists. In the automatic runoff round, the finalist who was given a higher score on a greater number of ballots is selected as the winner.

The concept was first proposed in October 2014 by Mark Frohnmayer, and was initially called score runoff voting (SRV). The runoff step was introduced in an attempt to reduce strategic incentives in ordinary score voting, such as bullet voting and tactical maximization. STAR is intended to be a hybrid between (rated) score voting and (ranked) instant runoff voting.

The first movement to implement STAR voting was centered in Oregon, with chapters in Eugene, Portland, Salem, Astoria, and Ashland. In July 2018, supporters submitted over 16,000 signatures for a ballot initiative in Lane County, Oregon, putting Measure 20-290 on the November 2018 ballot. This ballot measure did not pass, with 47.6% of voters voting yes, and 52.4% of voters voting no.

In 2019, the Multnomah County Democratic Party adopted STAR for all internal elections. A 2020 ballot initiative for the city of Eugene (in which a 54% majority had supported the 2018 county initiative) was attempted, as well as a second attempt at Lane County, and an initiative in Troutdale, Oregon. On July 27, 2020, after the Eugene City Council deadlocked at 4-4 on a vote to refer a measure allowing STAR voting to be used in city elections to the November 2020 ballot, Eugene Mayor Lucy Vinis cast the deciding vote against the referral, meaning that no Eugene ballot measure would be held in 2020.

The Independent Party of Oregon used STAR voting in their 2020 primary election. The Democratic Party of Oregon used STAR Voting for their elections for delegates to the 2020 Democratic convention. In 2022, the Libertarian Party of Oregon authorized STAR voting for its internal elections starting in 2023. In 2024, the city council of Oakridge, Oregon, voted 5-1 to place a STAR voting measure on the November ballot. The measure would have implemented STAR voting for the following three elections before holding a vote on whether to permanently adopt it. However, the measure failed with 46% approval.

Suppose Tennessee is holding an election on the location of its capital. The population is split between four cities, and all the voters want the capital to be as close to them as possible. The options are:

Suppose that 100 voters each decided to score from 0 to 5 stars each city such that their most liked choice got 5 stars, and least liked choice got 0 stars, with the intermediate choices getting an amount proportional to their relative distance.