K. S. Rao may refer to:

• Karnad Sadashiva Rao, Indian freedom fighter
• Kavuri Samba Siva Rao, Indian politician, engineer and industrialist

• OAO Aviakompania Sibir
• OA OmegA
• OA Omega
• OAO Sollers
• OAO Svobodny Railroad Car Repair Plant
• Oaphantes
• Oaphantes pallidulus
• OARAC
• Oaratlepolema forchhammeri
• Oarba
• Oarba de Mureș, Mureș
• O.A.R. (band)
• Oarblade
• Oardasaurus
• O.A.R. discography
• Oare Church
• Oare House
• Oare Meadow
• Oare Pavilion
• Oare (song)
• Oarisma edwardsii
• Oarlbeke
• Oar orbat
• OAS building
• Oase 1