| Name | Phone | Category |
| OB/GYN Associates, P.C. | (515) 964-3241 | Health Care |
| Oetken Law Firm, Inc. | (515) 964-4366 | Legal Services |
| Office Depot | (515) 306-7638 | Business Products |
| Okoboji Grill | (515) 964-9443 | Restaurants |
| Old Chicago | (515) 963-8686 | Restaurants |
| On With Life Community Services | (515) 964-2634 | Health Care |
| On With Life, Inc. | (515) 965-1339 | Health Care |
| Optimal Health Family Chiropractic Center | (515) 964-9966 | Health Care |
| Optimal Health Family Chiropractic Center | (515) 964-9966 | Health Care |
| Optimist Club of Ankeny | (515) 965-8420 | Organizations |
| Oral Surgeons, P.C. | (515) 965-9099 | Dental |
| O'Reilly Auto Parts | (515) 963-9322 | Automotive |
| Otter Creek Golf Course | (515) 965-6464 | Entertainment-Recreation |
| Our Financial Concierge | (515) 208-5706 | Finance |
| Our Lady's Immaculate Heart Catholic Church | (515) 964-3038 | Religious Affiliations |
| Outback Steakhouse | (515) 963-1243 | Restaurants |