All stand-alone novels in the same extended universe, they focus on contemporary teenage life in the UK and have received praise for their realism, LGBTQIA+ inclusion, and portrayal of mental health struggles.
Solitaire was praised for its compelling characters and Oseman's young age at the time of publishing, landing her a BBC Breakfast interview on 22 July 2014.
Upon "falling in love" with the characters of Nick and Charlie, Oseman decided their story needed further exploration and began the Heartstopper online webcomic series.
[11] The episodic comic first appeared online on Tumblr and Tapas in September 2016 and follows Tori's younger brother Charlie through high school as he meets and then begins dating Nick Nelson.
[14] The novel follows Frances Janvier, a high-achiever whose life revolves around her admission to the University of Cambridge, who meets the shy creator behind her favourite podcast, Aled Last.
Oseman noted that Frances' experience in Radio Silence was similar to her own school pressure and later disillusionment with academia following her education at Durham University.
The book explores Fandom culture, obsession, and identity alongside Oseman's trademark depictions of teenage friendship, sexuality and gender, and mental illness.
[29] Loveless tells the story of 18-year-old Georgia Warr as she begins her first year as a student at Durham University and who, despite being an avid fan fiction writer and lover of romance movies, has never kissed anyone or had a crush before.
[30] In addition to Georgia's personal journey of self-discovery as she realises she is aromantic and asexual, the book also discusses sexuality, identity, and discrimination within the LGBT community, as well as the effect of abusive relationships.
[32] She also emphasised the importance of writing a book centered around platonic love, stating that she "wanted to craft a story that had the structure of a romance but was about a friendship.
"[33] Loveless received positive critical reception from literary reviewers and media outlets, with many praising the novel's treatment of asexuality and its intersectional and diverse depiction of sexuality.
On 20 January 2021, it was revealed that a live-action television adaptation of Heartstopper was ordered to series by Netflix, with Oseman writing the script and Euros Lyn directing.
[48] It premiered on 22 April 2022, to critical acclaim with the first season receiving nine nominations and five wins, including Outstanding Young Teen Series, at the inaugural ceremony of the Children's and Family Emmy Awards.
[53] Season 3 was released on 3 October 2024 and was similarly praised for further developing the show's themes and for its nuanced and respectful discussion of mental health and relationship struggles.
[58] In July 2024, Oseman received an honorary degree from the University of Kent at a Rochester Cathedral graduation ceremony for Doctors of Letters and Arts.