Dubai International Airport, in Dubai, United Arab Emirates.

What is the difference between DXB and OMDB?

DXB is the IATA code, used commercially — tickets, timetables, luggage tags. OMDB is the ICAO code, used operationally by pilots and air traffic control, and assigned geographically by region.

Is DXB the same as DWC?

No. DWC is al Maktoum International, Dubai's second airport, intended to eventually replace DXB.

What airport is DXB?

DXB is

Dubai International Airport

Dubai, United Arab Emirates

Why the code is DXB

DuBai plus an X used as a separator, following the same 1930s convention that produced LAX.

This is the explanation in general circulation and it is very likely right, but no primary document has been published that settles it. Treated as an account rather than a fact.

The airport

IATA code: DXB
ICAO code: OMDB
Airport: Dubai International Airport
City: Dubai, United Arab Emirates
Opened: 1960
Code origin: The usual account, unverified

Dubai handles more international passengers than any other airport in the world, which is not the same as being the busiest overall — almost nobody flying through Dubai is going to Dubai. Concourse A was built specifically for the A380 and is the only terminal in the world dedicated to a single aircraft type.

Codes people book by mistake

Code	What it actually is
DWC	Al Maktoum International, Dubai's second airport, intended to eventually replace DXB.

The other code, OMDB

Every airport has two codes. The three-letter IATA code, DXB, is the one on your boarding pass and your luggage tag, and it is assigned for commercial use. The four-letter ICAO code, OMDB, is the one pilots and controllers use, and it is assigned geographically: the first letter or two identify the region, so every airport in the same part of the world shares a prefix. That is why OMDB looks nothing like DXB.

Common questions

What airport is DXB?: Dubai International Airport, in Dubai, United Arab Emirates.
Why is Dubai's airport called DXB?: DuBai plus an X used as a separator, following the same 1930s convention that produced LAX.
What is the difference between DXB and OMDB?: DXB is the IATA code, used commercially — tickets, timetables, luggage tags. OMDB is the ICAO code, used operationally by pilots and air traffic control, and assigned geographically by region.
Is DXB the same as DWC?: No. DWC is al Maktoum International, Dubai's second airport, intended to eventually replace DXB.

United Arab Emirates Capital, area, population and currency
The flag of United Arab Emirates Colours, symbols and lookalikes
Airport codes in United Arab Emirates 2 here
What airport is AUH? Zayed International Airport, Abu Dhabi

Sources

OurAirports — OurAirports (Public domain)

How these figures are compiled and checked