1/3

1/3 or $1/3$ may refer to:

Dates

 * January 3 (month-day date notation)
 * 1 March (day-month date notation)
 * January of the year 3 AD (month-year date notation)
 * March of the year 2024 AD (year-month date notation)

Other uses

 * $1/3$, a fraction of one third, or 0.333333333... in decimal.
 * pre-decimal British sterling currency of 1 shilling and 3 pence
 * 1st Battalion, 3rd Marines, United States infantry battalion
 * One/Three, a 20
 * Loona 1/3, a Loona spin-off