Plini Roessler-Holgate (born 1992 or 1993), known mononymously as Plini, is an Australian guitarist and songwriter. He began his career by releasing music under the name Halcyon, before switching to the use of his first name. Steve Vai described him as "the future of exceptional guitar playing", and the website MusicRadar named Plini the best prog guitarist of 2017.

Plini has released a trilogy of extended plays (Other Things and Sweet Nothings in 2013, The End of Everything in 2015). His debut album, Handmade Cities, which Vai described as "one of the finest, forward-thinking, melodic, rhythmically and harmonically deep instrumental guitar records [he has] ever heard", was released in 2016. Sunhead, an EP, was released in 2018, followed by his second full-length album, Impulse Voices, in 2020, and his third, An Unnameable Desire, in 2026.