What Is the Abbreviation for Oklahoma?
The standard abbreviation for Oklahoma is OK. This page explains why Oklahoma uses OK, how the code fits into the modern USPS system, what older printed abbreviations looked like, and which nearby or similar state codes people commonly confuse with it.
What Is the Abbreviation for Oklahoma?
Oklahoma's abbreviation is OK. You may also see Okla. in older writing, but OK is the form used in mailing addresses, forms, databases, and current style guides.
Use OK for Oklahoma in mailing addresses, shipping labels, official forms, and database records.
Why Oklahoma Uses OK
Oklahoma's USPS abbreviation is OK.
USPS adopted OK for Oklahoma in 1963. The older form Okla. still appears in older publications, but OK is the standard postal abbreviation today.
Old Abbreviation for Oklahoma
Before the USPS two-letter system became the mailing standard in 1963, printed reference books and newspapers often used longer abbreviations with punctuation. For Oklahoma, that older style was usually Okla..
That older form still appears in historical texts, archival material, and some legacy style guides, but the modern postal and database standard is OK. If someone searches for old abbreviation for Oklahoma, the practical answer is to recognize Okla. and use OK in current writing and addresses.
How to Write Oklahoma in an Address
In standard American addressing, the state line uses the city name followed by the two-letter code and ZIP Code. The abbreviation stays uppercase and does not take periods.
That same format applies in checkout forms, school worksheets, CRM exports, spreadsheets, shipping labels, and government databases — anywhere a two-letter state code is required.
OK Compared With Similar State Codes
OK is often checked against OH and OR because the O-state abbreviations can look similar in short lists and forms.
Related Abbreviation Questions
These states share a first letter, region, or alphabetical position with Oklahoma and are commonly checked alongside it.
Capital, Region, and Context
Oklahoma belongs to the South region. Its capital is Oklahoma City, and its postal code OK is used in addresses, forms, and databases throughout the country.
Oklahoma entered the Union on November 16, 1907.
FAQ
What is the abbreviation for Oklahoma?
The standard USPS abbreviation for Oklahoma is OK.
What is the postal abbreviation for Oklahoma?
OK is the two-letter postal abbreviation for Oklahoma. It is the form used in mailing addresses, shipping labels, forms, and databases.
How do you abbreviate Oklahoma?
Abbreviate Oklahoma as OK in current USPS, mailing, and database use.
Why is Oklahoma abbreviated OK?
Oklahoma's USPS abbreviation is OK.
What does OK stand for?
OK stands for Oklahoma in the USPS state abbreviation system.
What is the old abbreviation for Oklahoma?
Older editorial styles often wrote Oklahoma as Okla.. For mailing and database use, the modern standard is OK.
How do you write a Oklahoma mailing address?
Use the city name, then the two-letter postal code OK, then the ZIP Code. For example: Oklahoma City, OK 00000.
What state is OK?
OK is the postal abbreviation for Oklahoma, located in the South region. The capital is Oklahoma City.
Test All 50 State Abbreviations
Now that you know OK stands for Oklahoma, see how many of the other 49 you can get right. The M-states and I-states trip up most people.