The Masked Singer (abbreviated as TMS) is an American reality singing competition television series that premiered on Fox on January 2, 2019. It is part of the Masked Singer franchise that originated from the South Korean version of the show King of Mask Singer, which features celebrities singing songs while wearing head-to-toe costumes and face masks concealing their identities. Hosted by Nick Cannon, the program employs panelists who guess the celebrities' identities by interpreting clues provided to them throughout each season. Ken Jeong, Jenny McCarthy Wahlberg, Rita Ora, and Robin Thicke appear in each episode and vote alongside an audience for their favorite singer after all performances have concluded. The first least popular is eliminated, taking off their mask to reveal their identity.

To prevent their identities from being revealed before each prerecorded episode is broadcast, the program makes extensive use of code names, disguises, non-disclosure agreements, and a team of security guards. While television critics have had mixed reviews for the series and particularly negative opinions of its panelists, the costumes have attracted praise. Inspired by haute couture, they were designed in the first six seasons by Marina Toybina, who won a Costume Designers Guild Award and two Creative Arts Emmy Awards. Other production staff won or received nominations for various labor union awards, and the show has won or been nominated for awards presented by the Academy of Television Arts & Sciences, Critics Choice Association, and Hollywood Critics Association.

The first five seasons received the highest Nielsen ratings for a non-sports program in the key demographic of adults 18–49. Two spin-offs—an aftershow and a dance version, The Masked Dancer—followed as a result. The growth of the Masked Singer franchise has been credited to the show's success, as has an interest in adapting similar South Korean reality television series and other television formats centered on costumes. Media and merchandise associated with the series includes a podcast, clothing, accessories, NFTs, and a stage show.

The show's thirteenth season aired February–May 2025, with a fourteenth season scheduled to premiere in January 2026.

Each season of The Masked Singer features a group of celebrity contestants. In a typical episode, four to six contestants anonymously in costume each sing a 90-second cover for panelists and an audience. Hints to their identities—known as the "clue package"—are given before and occasionally after each performs. The perennial format is a taped interview with a celebrity's electronically masked voice narrating a video showing cryptic allusions to what they are known for. During screenings of the clue packages, after performances, and before an elimination, the panelists are given time to speculate on each singer's identity out loud and write comments in note binders. They may ask questions and the host may offer additional clues. After performances conclude, the audience and panelists vote for their favorite singer using an electronic device. The show uses a weighted voting system; panelists' and audience members' votes are worth 50 percent each and combined to form a score. The least popular contestant then takes off their mask to reveal their identity. This process of elimination continues for a set number of episodes until three contestants remain in the season finale, and one is declared the winner after they perform again. The "Golden Mask" trophy is awarded as a prize.

Voting does not occur for certain performances; contestants in an episode might occasionally sing as a group, and each episode concludes with the eliminated celebrity singing an encore unmasked. Occasionally, the eliminated celebrity sings their signature song unmasked. To continue attracting viewers, producers often modify the format each season. Except in the first, fifth and sixth seasons, a "smackdown" round is featured in select episodes in which the two least popular competitors from their first performances sing one after another on the same stage, and a second, eliminating vote occurs. Since the second season, the contestants are initially divided and only compete in a designated subgroup. A "Golden Ear" trophy awarded to the panelist with the most correct first impression guesses at the end of a season was introduced for the fourth, and until the sixth, as was a reduction of performances and the audience viewing and voting remotely. These elements continued in the fifth seasons, and "wildcard" contestants who perform at the end of certain episodes competed for the first time.

The permanent panel consists of actor and comedian Ken Jeong, television personality Jenny McCarthy Wahlberg, recording artist Nicole Scherzinger, and singer-songwriter Robin Thicke. A guest occasionally appears as a fifth panelist during an episode; Joel McHale has served as a guest panelist in almost every season, and previous seasons' winners have appeared. Nick Cannon hosts the show; his role was considered unclear in July 2020 after making anti-Semitic statements Fox said "inadvertently promoted hate". The network accepted Cannon's apology, and he pledged to donate his first paycheck from the fourth season to the Simon Wiesenthal Center after visiting with its officials. Niecy Nash acted as guest host for the first five episodes of the fifth season after Cannon tested positive for COVID-19. Recording artist Rita Ora, a panelist on the British version of the show, has substituted for Scherzinger since the eleventh season while Scherzinger appeared in the West End and Broadway revivals of Sunset Boulevard.

I turned around and all the diners were watching the TV screen. I saw a kangaroo in black pleather singing a pop song. At that moment I said, "Oh my gosh, I love this!" It was bizarre ... and it was still working. I found out that it was a hit format in Korea, it was a hit show in Thailand. And no one had the [U.S.] rights.