| 5041 | Odvjetnički zbor Osijek | http://www.ozos.org |
| 5042 | Odvjetnik Šakić | http://www.odvjetnik-sakic.hr |
| 5043 | OECD | http://www.oecd.org |
| 5044 | Off road 4x4 Barban | http://www.4x4barban.com |
| 5045 | Office shoes | http://www.officeshoes.hr |
| 5046 | Offset tisak | http://offset.hr |
| 5047 | Oikon d.o.o. | http://www.oikon.hr |
| 5048 | OK Grobničan | http://www.ok-grobnican.hr |
| 5049 | Okiroto d.o.o. | http://www.okiroto.hr |
| 5050 | OkoloNaOkolo, udruga | http://okolonaokolo.hr |
| 5051 | Oktal Pharma | http://www.oktal-pharma.hr |
| 5052 | O-K-teh d.o.o. | http://www.o-k-teh.hr |
| 5053 | Old Bridge Pub | http://www.oldbridgepub.hr |
| 5054 | Oldtimer klub Našice | http://www.oldtimer-nasice.hr |
| 5055 | Oldtimer klub Zagreb | http://www.oldtimer-klub-zagreb.hr |
| 5056 | Olinfos d.o.o. | http://www.olinfos.hr |
| 5057 | Oliva RMS d.o.o. | http://www.oliva-rms.hr |
| 5058 | Olival d.o.o. | http://www.olival.hr |
| 5059 | Olivari d.o.o. | http://www.volivari.com |
| 5060 | OLT d.d. Osijek | http://www.olt.hr |