 List of unnumbered minor planets: 2003 U (290–379)

The list of unnumbered minor planets, specifically those designated with the prefix "2003 U" in the range of 290 to 379, refers to a set of minor planets that were identified and given provisional designations but have not yet been assigned permanent numbers. Each of these provisional designations consists of a year (in this case, 2003) followed by a letter (U) and sometimes additional characters that help differentiate between multiple discoveries in the same year.