SYX may refer to:

• IATA airport code for Sanya Phoenix International Airport
• Skyway Airlines, airline code
• Smalltalk YX, an open source implementation of the Smalltalk-80 programming language

• Vieilles-Maisons-sur-Joudry
• Vieillespesse
• Vieille-Toulouse
• Vieillevie
• Vieillevigne
• Vieillevigne (disambiguation)
• Vieillevigne, Haute-Garonne
• Vieillevigne (Loire-Atlantique)
• Vieillevigne, Loire-Atlantique
• Vieilley
• Vieille-Église-en-Yvelines
• Vieilmoulin
• Vieira (footballer)
• Vieira, Joao
• Vieira, Joao Bernardo
• Vieira Lusitano
• Vieiras
• Vieira S.C.
• Vieiropolis
• Vieirópolis
• Viejas Band of Kumeyaay Indians
• Viejas casino
• Viejas Group of Capitan Grande Band of Mission Indians
• Viejas Indian Reservation
• Viejas mountain