Smilla Sundell


Smilla Sundell is a Swedish Muay Thai kickboxer. She competed in ONE Championship, where she was the former ONE Women's Strawweight Muay Thai World Champion.
On 22 April 2022 Sundell became the youngest person to ever win a world title in Muay Thai by defeating Jackie Buntan to win the inaugural ONE Women's Strawweight Championship at 17 years and 5 months. As of April 2024, she is ranked as the number two female featherweight Muay Thai contender in the world by the WBC Muaythai.

Early life

Born in Sundbyberg, Sweden, Sundell started practicing karate at five years old for self-defense. She first tried her hand at Muay Thai at 10 or 11, while on vacation in Thailand. Sundell and her family moved to Ko Samui when she was 12 years old due to her parents' careers. She and her younger sister started practicing Muay Thai at a gym called Yodyut Muay Thai due to a lack of any other sports. When Sundell was 15, her family moved back to Sweden. But she stayed in Thailand to pursue Muay Thai. Running out of opponents in Ko Samui and inspired by watching Stamp Fairtex, in October 2019 she moved to Pattaya and joined the Fairtex Gym, where she currently lives by herself.

Career

Early career

In early 2021, Sundell was ranked the number one female featherweight Muay Thai practitioner in the world by the WBC Muaythai at 16 years of age. She has notable victories over decorated champion Sawsing Sor Sopit, Ponpan Por.Muengpetch, and male fighter Bongsak Sitpholek. After amassing a record of 31 wins, 5 losses and 1 draw, Sundell signed with ONE Championship in 2021.

ONE Championship

In her ONE Championship debut at ONE: Full Circle on 25 February 2022, Sundell faced Australia's Diandra Martin. She won the fight by TKO in round 3. This was her first fight in four-ounce MMA gloves, which are smaller than the usual gloves used in Muay Thai.

ONE Women's Strawweight Muay Thai World Champion

Sundell faced Jackie Buntan for the inaugural ONE Women's Strawweight Muay Thai World Championship at ONE 156 on 22 April 2022. Sundell won by unanimous decision, making her the youngest person to ever win a world title. The fight also earned her a $50,000 Performance of the Night bonus.
Sundell made her kickboxing debut against Milana Bjelogrlić at ONE Friday Fights 18 on 26 May 2023. She won the fight by unanimous decision.
Sundell made her first Women's Muay Thai Strawweight World title defense against ONE Women's Atomweight Muay Thai World Champion Allycia Rodrigues at ONE Fight Night 14 on 29 September 2023. She retained the championship by a third-round technical knockout. She also earned her second $50,000 Performance of the Night bonus.
In the second title defense, Sundell faced Natalia Diachkova on 4 May 2024 at ONE Fight Night 22. At the weigh-ins, Sundell came in at 126.5 lb, 1.5 pounds over the strawweight limit for a title fight. As a result, Sundell was stripped of the title and only Diachkova was eligible to win it. She won the fight via technical knockout in the second round.
On 19 August 2025, it was reported that Sundell was removed from the ONE roster, her weight having exceeded its heaviest women's weight class.

Mixed martial arts career

On 26 October 2025, amateur MMA promotion Tuff-N-Uff announced that Sundell has signed with the organization and will be making her MMA debut in December.

Championships and awards

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Mixed martial arts record