OLS can stand for:
- IATA code for Nogales International Airport in Arizona
- Ordinary least squares, a method used in regression analysis for estimating linear models
- Ottawa Linux Symposium
- Oulun Luistinseura
- Olentangy Local School District (Delaware County, Ohio)
- The Sims 3: Outdoor Living Stuff, the third stuff pack to The Sims 3