Stopping Illicit Fentanyl Trafficking Act of 2023 or the SIFT Act of 2023 This bill permanently adds five fentanyl analogues and the entire category of fentanyl-related substances to schedule I of the Controlled Substances Act. A schedule I controlled substance is a drug, substance, or chemical that has a high potential for abuse; has no currently accepted medical value; and is subject to regulatory controls and administrative, civil, and criminal penalties under the Controlled Substances Act. Fentanyl-related substances are currently regulated under schedule I through a temporary order issued by the Drug Enforcement Administration. The temporary order expires on December 31, 2024. The bill also creates a process to remove from schedule I certain fentanyl-related substances that do not have a high potential for abuse.