Should I use British or American English on my resume?

Use the spelling most common where the job is based, and apply it consistently. British spelling ("organise", "colour", "programme", "licence") is usual in the UK, Ireland, Australia, New Zealand, India and many Gulf employers. American spelling ("organize", "color", "program", "license") is usual for US employers.

If you are unsure:

• Look at the job posting and the company website and follow their spelling.
• For international employers with no clear preference, either is fine if you are consistent.

Set your spell-checker to the matching variety, because it will otherwise "correct" words into the other spelling. Mixing both in one resume looks careless, even though neither is wrong.

Names are the exception. Keep official names exactly as written, such as a certificate called "Program Management Professional" or an employer whose name uses American spelling, even if the rest of your resume uses British spelling. Changing an official name can make it harder for employers to verify.