U-434 may refer to:

• {{GS|U-434}}, Type VII submarine launched in 1941; sunk in 1941 on her first patrol
• {{ship|Soviet submarine|B-515}}, (now known as U-434), a {{sclass2-|Tango|submarine}} built in 1976; currently a museum ship in Hamburg

• Olive-green Ufipa barb
• Olive-green ufipa Barb
• Olivegreen Ufipa barb
• Olivegreen Ufipa Barb
• Olive-Green ufipa Barb
• Olive-Green ufipa barb
• Olivegreen ufipa Barb
• Olive-Green Ufipa barb
• Olive Grevillea
• Olive grey
• Olive-grey
• Olive Griffith Stull
• Olive grove (disambiguation)
• Olive Grove Elementary School
• Olive groves
• Olive-Harvey College
• Olive-headed Brush-Finch
• Olive-headed Greenbul
• Olive Heights, Pasadena, California
• Olive Hill, California
• Olive Hill (disambiguation)
• Olivehill, Tennessee
• Olive Hill, Tennessee
• Olive Hughes
• Oliveira de azemeis