Tegomass was a Japanese pop duo active from 2006 to 2020, consisting of vocalists Yuya Tegoshi and Takahisa Masuda. Both members were also part of the larger boy band NEWS, and the group’s name is a portmanteau of their surnames. The duo was formed under the Johnny's Entertainment label with a specific goal of promoting Japanese pop music internationally, beginning with a debut in Sweden before releasing music in Japan.

The duo’s musical identity centered on vocal-driven ballads, often described as warm and tender, frequently incorporating orchestral strings, acoustic guitar, and piano. Their style was notably softer and more pop-focused than the work of their parent group NEWS, and they specialized in what some critics have characterized as Bacharach-style romantic pop songs.

Tegomass is best known in the context of anime for their contributions to the romantic comedy series Lovely Complex. In 2007, they released the single Kiss (Kaerimichi no Love Song), which served as the anime’s ending theme. The same single featured the track Kimi + Boku = Love?, which was used as the opening theme for the series. These songs remain their most recognized works connected to anime.

The following year, the duo continued their involvement with anime soundtrack work by contributing the song Ai Ai Gasa as the ending theme for the television anime Neo Angelique Abyss. The single was released on June 18, 2008, and became their second number-one single on the Oricon charts.

The duo released a total of six singles and four studio albums, with their debut album Tegomasu no Uta (2009) and its follow-up Tegomass no Mahou (2011) both reaching number one on the Oricon album chart. Other notable releases include the singles Tanabata Matsuri, Aoi Bench, and Sayonara ni Sayonara. Their discography also includes the extended play Tegomass no Ai, which was certified gold by the Recording Industry Association of Japan. Tegomass concert DVDs regularly topped Oricon’s music DVD chart as well.

The duo’s industry significance lies in their unusual international debut strategy, being the first Johnny's Entertainment act to release a single in Europe before Japan. Their debut single, Miso Soup, was released in Sweden in November 2006 in an English-language version, followed by a Japanese release the next month. Tegomass also represented Japan at the Golden Melody Awards in Taiwan in 2007. The group ended in June 2020 following Tegoshi’s departure from Johnny's Entertainment.