Niall Williams-Guthrie (née Williams; born 21 April 1988) is a New Zealand rugby league player.

[5][6] She was selected for their squad to the 2016 Summer Olympics, where New Zealand claimed the silver medal behind Australia.

[9][10] She was named in the Black Ferns Sevens squad for the 2022 Commonwealth Games in Birmingham.

[13][14] She also won a silver medal at the Rugby World Cup Sevens in Cape Town.

Of Samoan and European descent,[21] Niall, also known as "Nizzle",[22] is the younger sister of All Black Sonny Bill Williams.