Q4

Q4, Q-4 or q4 may refer to:
 * The fourth quarter of a calendar year
 * The fourth quarter of a fiscal year
 * Q4 (New York City bus), a bus line in Queens
 * Quake 4, a first-person shooter video game developed by Raven Software
 * Audi Q4 e-tron, a compact SUV
 * Swazi Express Airways IATA airline designator
 * Alfa Romeos All Wheel Drive (AWD) system
 * LNER Class Q4, a class of British steam locomotives
 * The Cunard Line codename for the ship later named Queen Elizabeth 2
 * A shortened name for Section 4, a part of Co-op City
 * An abbreviation for "quaque four" (every four) used in medical prescriptions
 * "Quran 4", the 4th chapter of the Islamic Holy book