Ground effect aerodynamics has been central to the performance of Formula One (F1) racing cars. By shaping the underfloor as Venturi tunnels, engineers can accelerate airflow beneath the chassis, reduce static pressure, and generate strong downforce with limited drag penalties. This idea was first applied in F1 during the late 1970s, later restricted, and reintroduced in the 2022 regulations. This paper reviews the fluid mechanics principles of the Venturi effect using Bernoulli’s equation and the continuity law, and summarizes how these principles are applied in modern racing. Wind tunnel experiments and computational fluid dynamics (CFD) models have shown that floor geometry, diffuser expansion angle, and ride height strongly influence downforce. Theoretical work further explains the physical mechanism of ground effect. Results from these studies indicate that Venturi tunnels can provide a large proportion of total downforce, while also introducing challenges such as “porpoising”. This review highlights the continuing importance of ground effect in motorsport and its relevance for vehicle aerodynamics more broadly.