Udayar may refer to:

• Udayar (novel), a Tamil novel by Balakumaran
• Udayar (title), a title or surname found in India
• Udayar (caste), a community found in Tamil Nadu

• 1885 general election
• 1885 Grand National
• 1885 Greek legislative election
• 1885 Hertford by-election
• 1885 Horsham by-election
• 1885 in Argentina
• 1885 in Australian literature
• 1885 in Brazil
• 1885 in Canadian football
• 1885 in Chile
• 1885 in China
• 1885 in comics
• 1885 in Costa Rica
• 1885 in Denmark
• 1885 in Germany
• 1885 in Liberia
• 1885 in Portugal
• 1885 in Scotland
• 1885 in Spain
• 1885 in Sweden
• 1885 Massachusetts Aggies football team
• 1885 Middlesex by-election
• 1885 Mid Kent by-election
• 1885 Mid Lincolnshire by-election
• 1885 Navy Midshipmen football team