Smith v. United States may refer to:
- Smith v. United States (1831)
- Smith v. United States (1836)
- Smith v. United States (1977), 431 U.S. 291 (1977), a case about federal obscenity prosecutions
- Smith v. United States (1993), 508 U.S. 223 (1993), a case about exchanging guns for drugs
- Smith v. United States (2013), 568 U.S. 106 (2013), a case about members leaving a drug conspiracy group
- Smith v. United States (2023)