'On Second Thought' or 'On Second Thoughts'? | Mastering Grammar

(Last Updated: 4 February 2024)

1. It is not idiomatic to include a possessive determiner (e.g. my, your, his, and her) in the fixed expression on second thought/thoughts.
2. A person follows advice. You could also say take up your idea or adopt your idea.
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Part 2

On Second Thought or On Second Thoughts: Which One Is Correct?

On second thought/thoughts is a common expression used when you want to change what you have said or decided. In British English, the word thought is usually pluralised (i.e. on second thoughts). In American English, the singular form is more common.

✅ (British English) We can do everything by ourselves. Actually, on second thoughts, maybe we can't. 
✅ (American English) We can do everything by ourselves. Actually, on second thought, maybe we can't.

✅ (British English) I thought I'd go shopping with Lucy, but on second thoughts I'd rather do some work at home.
✅ (American English) I thought I'd go shopping with Lucy, but on second thought I'd rather do some work at home.

✅ (British English) I want a fish burger. On second thoughts, I'll have a ham sandwich. 
✅ (American English) I want a fish burger. On second thought, I'll have a ham sandwich.

✅ (British English) On second thoughts, maybe you should sell your car and start going to work by bus.
✅ (American English) On second thought, maybe you should sell your car and start going to work by bus.

✅ (British English) Don't go anywhere till I come back, okay? No, on second thoughts, follow me.
✅ (American English) Don't go anywhere till I come back, okay? No, on second thought, follow me.

The Oxford Advanced Learner's Dictionary's entry for on second thoughts

Other Pages from the Same Book

Part 1: 'Desire Something' or 'Desire for Something'?
Part 3: 'Look For' or 'Find'?

Examples from the Media

British Cycling suggested that if he was now well enough to speak to the BBC, he was well enough to speak to their human resources department about his failure to keep proper medical records—and could also speak to UK Anti-Doping about their investigation into Team Sky, British Cycling and a medical package delivered for Sir Bradley Wiggins. Freeman responded by saying, on second thoughts, he was still too unwell to talk to anyone and quietly quit instead. —Daily Mail (2017)

On second thoughts, let's just go easy on the hormone therapy. —The Sydney Morning Herald (2002)

On second thought, Matt Kuchar will give his caddie a lot more money. —The New York Times (2019)

On second thought, maybe loading up a forward line with your three best players isn't such a bad idea after all. —Toronto Sun (2019)