Protein S-acylation is a dynamic lipid post-translational modification that can modulate the localization and activity of target proteins. In humans, the installation of the lipid onto target proteins is catalyzed by a family of 23 Asp-His-His-Cys domain-containing protein acyltransferases (DHHC-PATs). DHHCs are increasingly recognized as critical players in cellular signaling events and in human disease. However, progress elucidating the functions and mechanisms of DHHC “writers” has been hampered by a lack of chemical tools to perturb their activity in live cells. Herein, we report the synthesis and characterization of PATi, a pan- DHHC inhibitor more potent than 2-bromopalmitate (2BP), the most commonly used DHHC inhibitor in the field. Possessing an acrylamide warhead, PATi pairs its gain in potency with decreases in both toxicity and inhibition of the S-acylation eraser enzymes – two of the major weaknesses of 2BP. Our studies show that PATi engages with DHHC family proteins in cells, inhibits protein S-acylation, and disrupts DHHC-regulated cellular events. PATi represents an improved chemical tool for untangling the complexities of DHHC-mediated cell signaling by protein S-acylation.