Plant cellulose microfibrils are synthesized by a process that propels the cellulose synthase complex (CSC) through the plane of the plasma membrane. How interactions between membranes and the CSC are regulated is currently unknown. Here we demonstrate that all catalytic subunits of the CSC, known as cellulose synthase A (CESA) proteins, are S-acylated. Analysis of Arabidopsis CESA7 reveals 4 cysteines in variable region 2 (VR2) and 2 cysteines at the carboxy-terminus (CT) as S-acylation sites. Mutating both the VR2 and CT cysteines permits CSC assembly and trafficking to the Golgi, but prevents localization to the plasma membrane. Estimates suggest that a single CSC contains more than 100 S-acyl groups that greatly increases the hydrophobic nature of the CSC and likely influences its immediate membrane environment.