A mobile game spin-off of [[idolmaster|iDOLM@STER]] launched in 2014, this time focusing on producing for the male idols of the 315 Productions agency. 

The members of [[jupiter (idolmaster)|Jupiter]] from [[Idolmaster 2|iDOLM@STER 2]]'s 961 Productions are included in the roster, with Akizuki Ryou of [[idolmaster dearly stars|Dearly Stars]]' 876 Productions being added later as part of his own unit.

In March 2015, voices began to be introduced for the idols, starting with the unit DRAMATIC STARS. ST@RTING LINE, a series of music CDs featuring them and other units, also began to be released by Lantis throughout the year. 

In December 2015, a Twitter-based poll called the New Idol Discovery Project (新アイドル発掘オーディション) was run to select three new idols from a pool of nine candidates to form a new unit, with the winners being announced a month later. The winners (Amehiko, Koron, and Sora) were later implemented into the game in July 2016 as the idol group Legenders. The other six candidates have not been put into the game as of late.

In February 2017, Bandai Namco announced the development of [i][[idolmaster_side-m_live_on_stage!|The iDOLM@STER SideM Live on St@ge!]][/i], a mobile spinoff. The game serves as a male counterpart to [i][[idolmaster_cinderella_girls_starlight_stage|Starlight Stage]][/i], as it is a rhythm game utilizing 3D models of the 315 idols for in-game performances. They also announced a [i]SideM[/i] anime adaptation, with further details being revealed on "315 Day" (March 15). The anime premiered in the fall of 2017.

In 2021, a third game, [i][[idolmaster side-m growing stars|THE iDOLM@STER SideM GROWING STARS]][/i], was announced following the closure of [i]LIVE ON ST@GE![/i].

h4. Staff
* [[saitou_takashi_(idolmaster)|Saitou Takashi]]
* [[producer_(idolmaster_side-m)|Producer]]
* [[Yamamura Ken]]

h4. Idols

* [[Altessimo (idolmaster)|]]
** [[Tsuzuki Kei]]
** [[Kagura Rei]]

* [[Beit (idolmaster)|]]
** [[Watanabe Minori]] 
** [[Pierre Bichelberger]] 
** [[Takajo Kyoji]]

* [[cafe parade (idolmaster)|Café Parade]]
** [[Mizushima Saki]]
** [[Uzuki Makio]]
** [[Kamiya Yukihiro]]
** [[Shinonome Soichiro]]
** [[Asselin BB II]]

* [[Dramatic Stars (idolmaster)|]]
** [[Kashiwagi Tsubasa]]
** [[Tendo Teru]]
** [[Sakuraba Kaoru]]

* [[f-lags_(idolmaster)|F-LAGS]]
** [[Akizuki Ryo]]
** [[Tsukumo Kazuki]]
** [[Kabuto Daigo]]

* [[FRAME (idolmaster)|FRAME]]
** [[Kimura Ryu]]
** [[Akuno Hideo]]
** [[Shingen Seiji]]

* [[high x joker (idolmaster)|High×Joker]]
** [[Wakazato Haruna]]
** [[Iseya Shiki]]
** [[Akiyama Hayato]]
** [[Fuyumi Jun]]
** [[Sakaki Natsuki]]

* [[jupiter_(idolmaster)|Jupiter]]
** [[Amagase Touma]]
** [[Ijuuin Hokuto]]
** [[Mitarai Shouta]]

* [[Mofumofuen (idolmaster)|]]
** [[Tachibana Shiro (idolmaster)|]]
** [[Himeno Kanon]]
** [[Okamura Nao]]

* [[sai_(idolmaster)|Sai]]
** [[Kiyosumi Kuro]] 
** [[Hanamura Shoma]] 
** [[Nekoyanagi Kirio]] 

* [[S.E.M (idolmaster)|]]
** [[Yamashita Jiro]]
** [[Hazama Michio]]
** [[Maita Rui]]

* [[Shinsoku Ikkon (idolmaster)|]]
** [[Kurono Genbu]]
** [[Akai Suzaku]]

* [[The Kogado (idolmaster)|]]
** [[Enjoji Michiru]]
** [[Taiga Takeru]]
** [[Kizaki Ren]]

* [[w_(idolmaster)|W]]
** [[Aoi Kyosuke]]
** [[Aoi Yusuke]]

* [[Legenders (idolmaster)|]]
** [[Kitamura Sora]]
** [[Koron Chris]]
** [[Kuzunoha Amehiko]]

* New Idol Discovery Project Candidates 
** [[Andou Mario]]
** [[Igari Leo]]
** [[Kazama Shinobu]]
** [[Mimasaka Takeshi]]
** [[Sanjo Goro]]
** [[Shiraishi Eru]]

* [[C.FIRST (idolmaster)|]]
** [[Amamine Shu]]
** [[Hanazono Momohito]]
** [[Mayumi Eishin]] 

h4. In-universe productions

* [[Best Game (idolmaster side-m)|]]
* [[Beast Chronicle]]
* [[Cybernetics Wars]]
* [[Kiseki no Mahou NozoMira Melody]]

h4. External links

* "Official website":http://side-m.idolmaster.jp/
* "Anime website":http://imas-sidem.com/
* "Game Twitter":https://twitter.com/SideM_official
* "Project iM@S Wiki: THE iDOLM@STER: SideM":https://www.project-imas.wiki/THE_iDOLM@STER_SideM
アイドルマスターSideM SideM 【NL】SideM エムマス【腐】 エムマス