Cat 3 or CAT3 may refer to:

• Category 3 cable, an unshielded twisted pair cable
• Nanaimo/Long Lake Water Airport (ICAO airport code), Canada
• Cognitive Abilities Test 3, a test of reasoning abilities undertaken by students in the UK and Canada
• CAT III, an instrument landing system category
• CAT III, a measurement category used to classify live electric circuits
• LTE User Equipment Category3

• Aamer Iqbal (cricketer, born 1973)
• Aamer Iqbal (cricketer, born 1990)
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