A55 may refer to:

• A55 highway (Australia), a road connecting St George, Queensland and Lithgow, New South Wales
• A55 motorway (Canada), a road in Québec connecting Stanstead and Shawinigan
• A55 motorway (France), a road connecting Marseille and Martigues
• A55 road (Great Britain), a road connecting Chester and Holyhead
• Autostrada A55 (Italy), a bypass around Turin
• A55 road (Northern Ireland), a road around Belfast

• A-series light bulb of diameter 55 mm
• a model of a Fusion Controller Hub (FCH), a chipset used for AMD microprocessors
• Samsung Galaxy A55 5G, a mobile phone
• Sony Alpha 55, a DSLT camera
• Siemens A55, a mobile phone
• ARM Cortex-A55, a processor microarchitecture

• Old Indian Defense, Encyclopaedia of Chess Openings code
• Austin Cambridge A55, a British car
• GER Class A55, a British steam locomotive

• List of highways numbered 55