The Secure Takedown and Obstruction Prevention Act, or STOP Act, amends section 111 of title 18, United States Code, to establish a new federal offense related to resisting arrest. This legislation specifically targets individuals who engage in barricading oneself during arrest evasion when a federal law enforcement officer is performing official duties. The bill defines "barricade" as taking a physical position that prevents immediate access by an officer and refusing lawful orders to exit or comply, while knowing an apprehension is being attempted. Penalties for this offense include fines and imprisonment for up to 3 years, with enhanced penalties of up to 5 years if the violation creates a risk of or causes serious physical harm, involves possession of a deadly weapon, or endangers a third party present at the location. The Act also criminalizes aiding or assisting another person in such barricading conduct.