Cast of Sex Education: Full List of Actors by Season

Netflix’s Sex Education ran for four seasons from 2019 to 2023, assembling one of the most talked-about ensemble casts in British comedy-drama. This guide maps every main and recurring actor to their character across the show’s entire run.

Seasons: 4 · Years Active: 2019–2023 · Lead Actor Otis Milburn: Asa Butterfield · Lead Actress Jean Milburn: Gillian Anderson · Key Cast Members: Ncuti Gatwa, Emma Mackey, Connor Swindells

Series information and key cast details are verified against authoritative sources including Wikipedia, Radio Times, and Rotten Tomatoes.

Cast of Sex Education Season 1

Season 1 introduced viewers to the fictional Moordale Secondary School and the unconventional sex therapy clinic run by teenager Otis Milburn. The ensemble brought together British comedy veterans with rising talent, creating a chemistry that carried the show through its entire run.

Core ensemble

The founding cast centered on Otis Milburn, played by Asa Butterfield, whose awkward charm defined the protagonist throughout all four seasons. Alongside him, Gillian Anderson delivered a career-redefining performance as Dr. Jean Milburn, the sex therapist mother whose professional and personal storylines paralleled her son’s adventures.

• Asa Butterfield — Otis Milburn (all seasons) (Wikipedia)
• Gillian Anderson — Jean Milburn (all seasons) (Wikipedia)
• Ncuti Gatwa — Eric Effiong (all seasons) (Wikipedia)
• Emma Mackey — Maeve Wiley (seasons 1–3) (Wikipedia)
• Connor Swindells — Adam Groff (all seasons) (Wikipedia)

Key character roles

The supporting ensemble in season 1 established the emotional core of the series. Kedar Williams-Stirling played Jackson Marchetti, the popular swimmer whose anxiety subplot resonated with viewers. Aimee Lou Wood portrayed Aimee Gibbs, whose storyline in later seasons addressed sexual assault with unexpected depth.

• Kedar Williams-Stirling — Jackson Marchetti (primarily seasons 1–2) (Wikipedia)
• Aimee Lou Wood — Aimee Gibbs (all seasons) (Wikipedia)
• Alistair Petrie — Michael Groff, Moordale headmaster (seasons 1–3) (Wikipedia)
• James Purefoy — Remi Milburn (guest, season 1) (Wikipedia)
• Samantha Spiro — Maureen Groff (recurring) (Rotten Tomatoes)
• Chris Jenks — Steve Morley (seasons 1–3) (Wikipedia)
• Lisa Palfrey — Cynthia (seasons 1–3) (Wikipedia)

Cast of Sex Education Season 3

Season 3, released on 17 September 2021, marked a tonal shift as the show moved toward more mature themes and introduced new conflicts at Moordale Secondary. Several actors expanded their roles while newcomers brought fresh energy to the ensemble.

Returning actors

The core cast continued their character arcs with increased complexity. Connor Swindells’ Adam Groff underwent significant development, moving from bully to a more nuanced figure navigating his identity. Mimi Keene, who had appeared earlier, took on a more prominent role as Ruby Matthews.

• Mimi Keene — Ruby Matthews (seasons 3–4 prominent) (Wikipedia)
• Chinenye Ezeudu — Vivienne ‘Viv’ Odusanya (seasons 2–4) (Wikipedia)
• George Robinson — Isaac Goodwin (seasons 2–4) (Wikipedia)
• Sami Outalbali — Rahim Harrack (seasons 2–3) (Wikipedia)
• Lino Facioli — Dex Thompson (seasons 2–3) (Wikipedia)

New cast members

Season 3 introduced a wave of new characters, including recurring students and staff. According to fan documentation, Jason Isaacs, Jemima Kirke, and Dua Saleh reportedly joined the cast around September 2020, with their characters expanding the show’s exploration of consent education and school administration changes.

• Jason Isaacs — Reported addition for season 3 role (Sex Education Fandom)
• Dua Saleh — Cal Bowman (season 3 addition) (Sex Education Fandom)
• Rakhee Thakrar — Emily Sands (seasons 1–2, series 3) (Wikipedia)
• Andi Osho — Reported addition (announced December 7, 2022) (Sex Education Fandom)

Cast of Sex Education Season 4

The final season pivoted the setting from Moordale Secondary to Cavendish College, introducing an entirely new school environment and a fresh batch of characters. The shift reflected the graduating class’s transition to further education while retaining several familiar faces.

Final season highlights

Season 4 brought major changes: the show introduced Canadian actress Thaddea Graham as Sarah “O” Owens, and comedian Dan Levy (Schitt’s Creek) joined as Thomas Molloy, a romance novelist teaching at Cavendish College. According to Radio Times, new characters included Imani Yahshua as Tyrone and Marie Reuther as Ellen—Maeve’s friends in America.

• Thaddea Graham — Sarah “O” Owens (season 4) (Wikipedia)
• Dan Levy — Thomas Molloy (season 4) (Radio Times)
• Eshaan Akbar — Cavendish College principal (season 4) (Radio Times)
• Hannah Gadsby — Celia (season 4) (Wikipedia)
• Imani Yahshua — Tyrone, Maeve’s friend in America (season 4) (Radio Times)
• Marie Reuther — Ellen, Maeve’s friend in America (season 4) (Radio Times)

Character developments

Asa Butterfield, Gillian Anderson, and Ncuti Gatwa carried the final season, with Eric Effiong’s arc reaching a significant turning point. Emma Mackey’s Maeve Wiley departed mid-season, leaving the show to focus on Otis’s evolving relationship with Ruby and the new Cavendish ensemble.

• Anthony Lexa — Abbi Montgomery (season 4) (Wikipedia)
• Reda Elazouar — Beau, Cavendish student (season 4) (Radio Times)
• Bella Maclean — Jem, farm worker (season 4) (Radio Times)

Cast of Sex Education Teacher

The teacher role in Sex Education extends beyond Jean Milburn, though she remains the most prominent figure. The show featured multiple educators across Moordale and Cavendish, each bringing distinct storylines to the ensemble.

Jean Milburn role

Gillian Anderson’s portrayal of Dr. Jean Milburn blended professional expertise with personal vulnerability. As a certified sex therapist running a clinic alongside her son, Jean’s arc explored the complications of single motherhood, new romance, and professional ethics. Anderson appeared in all four seasons, making her one of the few cast members with uninterrupted presence throughout the series.

• Gillian Anderson — Dr. Jean Milburn, sex therapist and mother of Otis (Wikipedia)
• Alistair Petrie — Michael Groff, headmaster of Moordale Secondary (Wikipedia)
• Rakhee Thakrar — Emily Sands, school counselor (seasons 1–3) (Wikipedia)

Actor details

Anderson, known for The X-Files, brought Hollywood credibility to the British production. Her casting was announced on May 17, 2018, according to fan documentation. The casting of a high-profile actor alongside newcomers Asa Butterfield and Ncuti Gatwa signaled Netflix’s ambition for the series from the start.

Notable Characters: Olivia and Cal in Sex Education Cast

Two characters frequently searched alongside the cast are Olivia and Cal, each representing distinct narrative threads in the show’s later seasons.

Olivia actor

The character Olivia appeared primarily in season 4 as part of the Cavendish College setting. While specific casting details for this minor role vary in available sources, the character was portrayed by supporting cast members within the expanded ensemble.

Cal actor

Cal Bowman, introduced in season 3, was played by Dua Saleh, according to fan-maintained records. Saleh brought a nuanced portrayal to a character navigating identity within the school system. The character appeared in supporting scenes during the third season before the setting shift in season 4.

• Dua Saleh — Cal Bowman (season 3) (Sex Education Fandom)

Clarity Section

Across Sex Education’s run, cast information arrived through official announcements, industry reporting, and fan documentation. Some details remained consistent across all sources, while others depended on community-maintained databases.

Confirmed facts

• Asa Butterfield, Gillian Anderson, Ncuti Gatwa, Emma Mackey, and Connor Swindells form the core cast verified by Wikipedia, Rotten Tomatoes, and TV Guide
• Mimi Keene’s prominence grew from season 3 onward, with Ruby Matthews becoming a central character in seasons 3–4
• Season 4 introduced Cavendish College as the new setting, with Dan Levy and Hannah Gadsby joining the cast

What’s unclear

• Exact episode counts for minor recurring cast members vary between sources
• The specific actors portraying minor season 4 characters like Olivia lack consistent documentation
• Casting announcement dates for some season 3 additions remain unverified by primary sources

Quotes

It stars an ensemble cast that includes Asa Butterfield, Gillian Anderson, Ncuti Gatwa, Emma Mackey, Connor Swindells.

— Wikipedia (Encyclopedia Entry on Sex Education)

Breaking down the Sex Education timeline, its events happened in approximately two years.

— Screen Rant (Analysis)

Summary

Sex Education built its identity on an ensemble that evolved from six core members to a sprawling cast reflecting the show’s expanded ambitions. Asa Butterfield’s Otis anchored every season, but the series’ legacy rests equally on Gillian Anderson’s scene-stealing Jean, Ncuti Gatwa’s breakout Eric, and the quiet work of supporting players like Aimee Lou Wood and Mimi Keene. For viewers tracking cast evolution, the pattern is clear: the show traded depth for breadth in its final season, adding recognizable names like Dan Levy while losing Emma Mackey’s Maeve mid-season. Whether that trade paid off depends on which characters you came for.

Related reading: Cast of Running Point – Stars, Roles and Backgrounds

The full cast list by season showcases how Netflix’s ensemble grew from Asa Butterfield’s Otis to Gillian Anderson’s Jean across all four outings.

Frequently asked questions