The sixth season of the American television series Agents of S.H.I.E.L.D., based on the Marvel Comics organization S.H.I.E.L.D., follows S.H.I.E.L.D.

The season is produced by ABC Studios, Marvel Television, and Mutant Enemy Productions, with Jed Whedon, Maurissa Tancharoen, and Jeffrey Bell serving as showrunners.

Clark Gregg, who portrays Coulson in the series and films, returns as the new character Sarge in the season, alongside series regulars Ming-Na Wen, Chloe Bennet, Iain De Caestecker, Elizabeth Henstridge, Henry Simmons, and Natalia Cordova-Buckley.

It received positive reviews, with praise for its lighter tone and pacing, which critics credited to its shorter run of episodes in comparison to previous seasons.

receiving a renewal for a sixth season,[22] but in March, Nellie Andreeva of Deadline Hollywood described the series as being "on the bubble", meaning it "could go either way".

The writers had not intended this when they first introduced the objects, but when approaching the sixth season they wanted a way to have Sarge be created from Coulson and used the monoliths established control over space, time, and manifesting fear to do so.

[35] At San Diego Comic-Con 2018, main cast members Ming-Na Wen, Chloe Bennet, Iain De Caestecker, Elizabeth Henstridge, Henry Simmons, and Natalia Cordova-Buckley were confirmed to return from previous seasons as Melinda May, Daisy Johnson / Quake, Leo Fitz, Jemma Simmons, Alphonso "Mack" Mackenzie, and Elena "Yo-Yo" Rodriguez, respectively.

Tancharoen stated that they would be explored more in this season, with the executive producers all agreeing that they had grown to love the characters just as the fans had.

[16][21] In April 2018, Karolina Wydra, Christopher James Baker, and Barry Shabaka Henley were announced as cast in the roles of mercenary Izel, assassin Malachi, and natural science professor Marcus Benson.

[31] In May, with the season's premiere, several recurring actors were revealed to be portraying members of Sarge's team: Brooke Williams as Snowflake, Winston James Francis as Jaco, and Matt O'Leary as Pax.

[18] Shainu Bala also recurs in the season as agent Trevor Khan,[19] while Maurissa Tancharoen has a role as Deke's girlfriend Sequoia.

[42][43] The Quake symbol on the costume's back is also retained, and updated with "contrasting leather panels to make it pop".

[45] After the emotional fifth-season finale, Wen felt that returning for the sixth season with Gregg directing was "wonderful out of the gate, and like we got a new life".

[49] When asked how the season would connect to the then-upcoming MCU film Avengers: Endgame, Marvel Television head Jeph Loeb suggested in March 2019 that the one year time jump between the previous season of the series and this one was part of the series' tie-in to that film.

[32] Endgame is a direct sequel to Avengers: Infinity War (2018), which saw the death of half of all life in the universe beginning shortly after the events of Agents of S.H.I.E.L.D.

After Endgame was released in April, the showrunners and Loeb revealed that the series would not be depicting this loss of life for several reasons: they began production on the season without knowing all of Endgame's plot or how Spider-Man: Far From Home (2019) would be depicting a post-Endgame MCU; they were unsure when the season would be released in relation to Endgame and how much they would be allowed to reveal if they had begun airing before the film was released; and they wanted to focus on telling their own story rather than be "shackled too much to the universe-changing events from the films".

They acknowledged that this meant the series no longer lined-up with the films' timeline, but Whedon said the writers had an explanation for this that made sense to them even though they did not plan to "burden the audience" with it.

[50] The season has some thematic similarities with Endgame, as both depict their heroes dealing with loss, which Whedon said was "not a coincidence" and described as "the nature of these stories".

[57] Since the season was set to air after the release of Avengers: Endgame, Dungey noted in May 2018 that the decision to schedule it then was ABC's, and not in accordance with any of Marvel Studios' larger MCU plans.