Isaah Patrick Ferguson-Yeo (born 6 November 1994) is an Australian professional rugby league footballer who plays as a lock and second-row forward for the Penrith Panthers in the NRL and Australia at international level.

In February 2017, Yeo was named as the captain of Penrith's 2017 NRL Auckland Nines squad, The Panthers were the runner-ups of the tournament, losing to the Sydney Roosters 10-8 in the final.

[15][16] Yeo made 26 appearances for Penrith and scored 4 tries in 2018 as the club finished 5th on the table at the end of the regular season.

Penrith reached the second week of the finals for the third season running but were eliminated by the Cronulla-Sutherland Sharks 21-20 with Yeo scoring a try in the defeat.

[17] Yeo began the 2019 as one of Penrith's first choice second-rowers and played in the club's opening round loss against Parramatta.

[18][19] Yeo made a total of 18 appearances for Penrith in the 2019 NRL season as the club finished a disappointing 10th on the table and missed out on the finals for the first time since 2015.

[21] In Game 2 of the 2020 State of Origin series, Yeo made his debut off the bench for New South Wales in a 34-10 win.

[24] With a final score of 14-12, Penrith held out a late barrage by South Sydney Yeo played all 80 minutes, making 168 metres, 57 post-contact metres and 36 tackles[25][26] On 29 May, Yeo was selected by New South Wales to play in game one of the 2022 State of Origin series.

[29] Yeo played for Australia in their 2021 Rugby League World Cup final victory over Samoa.

[30] On 18 February, Yeo played in Penrith's 13-12 upset loss to St Helens RFC in the 2023 World Club Challenge.

[36] Yeo played 25 games for Penrith in the 2024 NRL season including the clubs 14-6 grand final victory over Melbourne.