Siobhán Kate Cullen is an Irish actress. She began her career as a child actress, making her debut in Marina Carr's play "By the Bog of Cats" (1998) at the Abbey Theatre. She got her first major screen role in Eoin Macken's horror film "The Inside" (2012).

Cullen has played roles in the RTÉ1 and BBC One miniseries "Paula" (2017), the ITV adaptation "The Long Call" (2021), the BritBox series "The Dry" (2022–2024), the RTÉ series "Obituary" (2023–) and the Netflix series "Bodkin" (2024). She was named a Screen International "Star of Tomorrow" in 2022.