Case theory may refer to:

• Grammatical case theory, in grammar
• Case theory (in law)

• Sohrschied
• Sohrwardia
• Sohryu Asuka Langley
• Sohryuden
• Sohryuden: Legend of Four Kings
• Sohrāb
• Sohsuke Takaoka
• Sohu.com
• SOH/V-broken
• Sohüta
• Soi
• SOIA
• SoIaF
• Soia Mentschikoff
• So I Begin
• SO IC
• Soi Cheang
• Soi Cheang Pou-Soi
• Soichi Fujita
• Soichiro Fukutake
• Soichiro Hoshi
• Soichiro Kuzuki
• Soichirou Hoshi
• Soichiro Watase
• Soi Dao District