Alistair Williams is a British special effects supervisor, registered with the Joint Industry Grading Scheme (JIGS) and a member of the Institute of Explosives Engineers. Over nearly three decades in the film industry, he has risen from technician roles to supervising practical special effects on major studio features. His team and management system at Phantasm—a company he leads that specialises in special effects, motion control, special props, and real-time previsualization software—have earned a Silver Award from the Royal Society for the Prevention of Accidents (RoSPA) for health and safety management.

Williams has served as special effects supervisor or production special effects supervisor on high-profile blockbusters such as Fast & Furious Presents: Hobbs & Shaw (2019), F9: The Fast Saga (2021), Fantastic Beasts: The Secrets of Dumbledore (2022), Pinocchio (2022), Fast X (2023), Indiana Jones and the Dial of Destiny (2023), and The Fantastic Four: First Steps (2025).

At the 22nd Visual Effects Society (VES) Awards in early 2024, Williams received two nominations for his work on Indiana Jones and the Dial of Destiny: one for Outstanding Visual Effects in a Photoreal Feature (shared with Andrew Whitehurst, Kathy Siegel, Robert Weaver, and Julian Hutchens) and another for Outstanding Created Environment in a Photoreal Feature (shared with Johan Gabrielsson, Adrian Tsang, Stefan Andersson, and Martin Eneroth-Johansson). Earlier, his visual effects contributions on Fantastic Beasts: The Secrets of Dumbledore also garnered a VES nomination for Outstanding Visual Effects in a Photoreal Feature, where he was recognised alongside Benjamin Loch, Christian Mänz, Stéphane Nazé, and Olly Young.

Beyond supervising physical effects, Williams co-founded Phantasm VV, a division of Phantasm that develops virtual visualisation tools using game engines and 3D scanning to streamline communication, safety and efficiency on action-heavy sequences.