American actress Sadie Sink posing for a photo at the Disney Entertainment Showcase at D23: The Ultimate Disney Fan Event in Anaheim, California.

Matt Winkelmeyer // Getty Images for Disney

The 10 fastest-growing US Instagram accounts of August 2026

Marvel’s D23 publicity cycle was the dominant verified theme among August 2026’s fastest-growing U.S. Instagram accounts, powering four of the top 10 entries. Sadie Sink led the list after debuting as Jean Grey and appearing at Disney’s D23 Expo, while Dolly Parton’s death on Aug. 25 drove a memorial-fueled surge to the No. 2 spot. Beyond Hollywood’s franchise machine, a viral Drake livestream moment and a breakout Prime Video premiere produced the month’s clearest examples of independent and emerging-talent growth. Net Influencer compiled the full ranking of the fastest-growing Instagram accounts in the U.S. for last month.

#1. Sadie Sink | @sadiesink_

A post shared by Sadie Sink (@sadiesink_)

Gained: +2.1M followers
August total: 34.8M followers

Sink appeared at Disney’s D23 Expo on Aug. 14 after debuting as Jean Grey in “Spider-Man: Brand New Day” to promote the newly announced “X-Men” film, as “Brand New Day” continued its run past $2 billion worldwide.

#2. Dolly Parton | @dollyparton

A post shared by Dolly Parton (@dollyparton)

Gained: +1.5M followers
August total: 10.1M followers

Country music legend Dolly Parton died on Aug. 25 after a brief battle with cancer, prompting a wave of public tributes from fans, fellow musicians, and officials across social media.

#3. Inde Navarrette | @indenavarrette

A post shared by Gap (@gap)

Gained: +1.2M followers
August total: 5.1M followers

Navarrette was revealed as Rogue in the upcoming “X-Men” film during Disney’s D23 Expo on Aug. 14, extending a breakout year that began with her acclaimed performance in the horror hit “Obsession.”

#4. Robert Downey Jr. | @robertdowneyjr

A post shared by Robert Downey Jr. (@robertdowneyjr)

Gained: +1.0M followers
August total: 58.7M followers

Downey appeared at D23 on Aug. 14 as Marvel showcased new footage from “Avengers: Doomsday,” ahead of the film’s December release. Downey is playing Doctor Doom in the new film.

#5. Zendaya | @zendaya

A post shared by Zendaya (@zendaya)

Gained: +963K followers
August total: 178.0M followers

Zendaya rode the record-breaking box office run of “Spider-Man: Brand New Day,” which crossed $1 billion worldwide in six days in early August, the second-fastest film ever to hit that mark.

#6. MrBeast | @mrbeast

A post shared by MrBeast (@mrbeast)

Gained: +903.7K followers
August total: 89.1M followers

After announcing his marriage to gaming streamer Thea Booysen in July, YouTube sensation MrBeast kept pace with his regular content upload schedule in August.

#7. Mayor Zohran Kwame Mamdani | @nycmayor

A post shared by Mayor Zohran Kwame Mamdani (@nycmayor)

Gained: +878.5K followers
August total: 4.7M followers

The mayor of New York City drew sustained national coverage over his administration’s pied-à-terre tax rollout (first announced in July) and an ethics complaint filed by a Washington, D.C.-based watchdog group over the use of official events to endorse Democratic candidates.

#8. Lin Lamar | @pinkchyuwu

A post shared by Lin Lamar (@pinkchyuwu)

Gained: +716.9K followers
August total: 3.0M followers

Lamar went viral on Aug. 8 after appearing in a ‘20 v 1’ dating segment on rapper Drake’s Kick livestream, where a clip of her getting him to bark on camera spread widely.

#9. Marvel Entertainment | @marvel

A post shared by Marvel Studios (@marvelstudios)

Gained: +696K followers
August total: 65.1M followers

Marvel anchored a blockbuster D23 Expo weekend with new looks at “Avengers: Doomsday” and the upcoming Vision series “VisionQuest,” plus the new “X-Men” cast reveal.

#10. Ella Rubin | @ellarubin1

A post shared by Ella Rubin (@ellarubin1)

Gained: +689.5K followers
August total: 774.2K followers

Rubin starred in “Sterling Point,” which premiered on Amazon Prime Video on Aug. 5 as a No. 1 global hit and was renewed for a second season by Aug. 20.

The D23 Effect

Four of the 10 accounts trace directly back to Disney’s D23 Expo, held Aug. 14-16 in Anaheim, California, all confirmed via Disney, Marvel, and Deadline’s event coverage:

  • Sadie Sink: Promoted the new “X-Men” film after debuting as Jean Grey in “Spider-Man: Brand New Day.”
  • Robert Downey Jr.: Appeared for the new “Avengers: Doomsday” footage.
  • Marvel Entertainment: Account served as a hub for the full weekend of reveals.
  • Inde Navarrette: Revealed as Rogue on the same D23 stage as Sink, in the same “X-Men” cast announcement.

Data from HypeAuditor, 2026

This story was produced by Net Influencer and reviewed and distributed by Stacker.