SLO can refer to:
- Salem-Leckrone Airport (IATA airport code), Salem, Illinois
- San Luis Obispo, California
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- California Polytechnic State University (Cal Poly San Luis Obispo, frequently called Cal Poly SLO or just SLO)
- Scanning laser ophthalmoscopy, a method of examination of the eye
- Service level objective, which is similar to a service level agreement
- The IOC country code for Slovenia (the FIFA and ISO 3166-1 code is SVN)
- Sword-like object, a sword meant only for display
- Software life-cycle object, a concept used in Computer Science
- Symmetrical lupoid onychodystrophy, a canine autoimmune nail disease