| OBCL Limited | OBCL | Services |
| Oberoi Realty Limited | OBEROIRLTY | Realty |
| OBSC Perfection Limited | OBSCP | — |
| OCCL Limited | OCCLLTD | Commodities |
| Odigma Consultancy Solutions Limited | ODIGMA | Information Technology |
| Oil & Natural Gas Corporation Limited | ONGC | Oil Gas & Consumable Fuels |
| Oil Country Tubular Limited | OILCOUNTUB | Energy |
| Oil India Limited | OIL | Oil Gas & Consumable Fuels |
| Ola Electric Mobility Limited | OLAELEC | Automobile and Auto Components |
| Olectra Greentech Limited | OLECTRA | Automobile and Auto Components |
| Om Freight Forwarders Limited | OMFREIGHT | Services |
| OM INFRA LIMITED | OMINFRAL | Industrials |
| Om Power Transmission Limited | OMPOWER | Industrials |
| Omax Autos Limited | OMAXAUTO | Consumer Discretionary |
| Omaxe Limited | OMAXE | Consumer Discretionary |
| Omfurn India Limited | OMFURN | — |
| Omnitech Engineering Limited | OMNI | Industrials |
| On Door Concepts Limited | ONDOOR | — |
| One 97 Communications Limited | PAYTM | Financial Services |
| One Mobikwik Systems Limited | MOBIKWIK | Financial Services |
| One Point One Solutions Limited | ONEPOINT | Services |
| Oneclick Logistics India Limited | OLIL | — |
| Onelife Capital Advisors Limited | ONELIFECAP | Financial Services |
| OnEMI Technology Solutions Limited | KISSHT | Financial Services |
| Onesource Specialty Pharma Limited | ONESOURCE | Healthcare |
| Onida Electronics Limited | ONIDA | Consumer Discretionary |
| OnMobile Global Limited | ONMOBILE | Consumer Discretionary |
| Onward Technologies Limited | ONWARDTEC | Information Technology |
| Onyx Biotec Limited | ONYX | — |
| Optiemus Infracom Limited | OPTIEMUS | Telecommunication |
| Optivalue Tek Consulting Limited | OPTIVALUE | — |
| Oracle Financial Services Software Limited | OFSS | Information Technology |
| Orbit Exports Limited | ORBTEXP | Consumer Discretionary |
| Orchasp Limited | ORCHASP | Information Technology |
| Orchid Pharma Limited | ORCHPHARMA | Healthcare |
| Oriana Power Limited | ORIANA | — |
| Oricon Enterprises Limited | ORICONENT | Industrials |
| Orient Bell Limited | ORIENTBELL | Consumer Discretionary |
| Orient Cement Limited | ORIENTCEM | Construction Materials |
| ORIENT CERATECH LIMITED | ORIENTCER | Industrials |
| Orient Electric Limited | ORIENTELEC | Consumer Discretionary |
| Orient Green Power Company Limited | GREENPOWER | Utilities |
| Orient Paper & Industries Limited | ORIENTPPR | Commodities |
| Orient Press Limited | ORIENTLTD | Industrials |
| Orient Technologies Limited | ORIENTTECH | Information Technology |
| Oriental Aromatics Limited | OAL | Commodities |
| Oriental Hotels Limited | ORIENTHOT | Consumer Discretionary |
| Oriental Trimex Limited | ORIENTALTL | Consumer Discretionary |
| Orkla India Limited | ORKLAINDIA | Fast Moving Consumer Goods |
| ORTIN GLOBAL LIMITED | ORTINGLOBE | Healthcare |
| Osel Devices Limited | OSELDEVICE | — |
| Osia Hyper Retail Limited | OSIAHYPER | — |
| Oswal Agro Mills Limited | OSWALAGRO | Services |
| Oswal Greentech Limited | OSWALGREEN | Financial Services |
| Oswal Pumps Limited | OSWALPUMPS | Capital Goods |
| Owais Metal And Mineral Processing Limited | OWAIS | — |