Niamh Lucy Peacock (born 22 March 2008) is an English professional footballer who plays as a defender for Women's Super League 2 club Portsmouth, on an Academy Development Registration from Arsenal. She has represented England at the under-15, under-17, and under-20 levels. She is the first-ever player in WSL2 history to be signed on an Academy Development Registration (ADR).
Peacock began playing football at the age of five, joining her local team, Isleworthians Youth FC, where she was the only girl on the team.
She was encouraged to attend a Chelsea FC Talent ID session aged 5 & a half, and impressed the club but was too young to play for their U7s team. However, Chelsea allowed her to attend their weekly sessions and Peacock stayed with them for a season and a half before trialling for Arsenal Women's U9âÂÂs Player Development Centre Team.
After a successful trial, Peacock officially joined the Arsenal academy at the age of eight, where she initially played as a midfielder.
Peacock has represented Arsenal up to the under-21 level. She captained the team as they won the PGA League Under-21 Division One title in the 2024âÂÂ25 season. She was called up to the senior team for the first time on 29 January 2025, where she was an unused substitute in Arsenal's 5âÂÂ0 win over Bristol City in the fourth round of the FA Cup.
On 20 August 2025, it was announced that Peacock had joined FA Women's National League South side Watford on a dual-registration contract. She made her debut for the club on the same day, featuring in a 7âÂÂ0 win over Charlton Athletic PGA.
On 30 January 2026, Peacock signed with WSL2 club Portsmouth, becoming the first player in the league's history to be signed on an Academy Development Registration, which allows the player to continue training with their parent club's academy while playing competitive matches for another club. She made her debut for Portsmouth on 8 February 2026, coming on as a substitute in a 2âÂÂ1 loss against Ipswich Town.
Peacock has represented England at the under-15, under-17, under-19, and under-20 levels. She was part of the U17 squad at the FIFA Under-17 Women's World Cup in the Dominican Republic. She played for England during the qualification campaign for the 2026 UEFA Women's Under-19 European Championship.