Keep an eye on
/kiːp ən ˈaɪ ɒn/neutral, informalUK · US · AU · IE · CA
What does “Keep an eye on” mean?
Keep an eye on means watch someone or something carefully to make sure they are safe or doing the right thing.
This phrase means to pay attention to someone or something over a period of time. It often implies checking for problems, keeping a child safe, or guarding an object so it does not burn or get stolen.
It is one of the most common everyday idioms in English. You can use it comfortably with family, friends, or coworkers without sounding too casual or too formal.
When do people say it?
People use this phrase when asking someone to look after a person, a pet, or a task for a short time.
“Can you keep an eye on the soup while I answer the door?”
Is it formal or informal?
Register: neutral, informal. It is most at home in both everyday conversation and professional writing. Most common in UK and US and AU and IE and CA.
Where does it come from?
This phrase has been used in English since at least the 16th century. It comes from the simple idea of directing your vision toward something you want to protect or monitor.
Origin confidence: Well documented
How do you say “Keep an eye on” in other languages?
Last reviewed 2026-09-11