Truss, the favourite to succeed Boris Johnson as the UK’s prime minister, also said: “The best thing to do with Nicola Sturgeon is ignore her.”
Her choice of words represents a significant hardening of her language over Scotland, and is likely to prompt an angry response from Scottish nationalists.
The first referendum in 2014 saw the pro-UK campaign win by 55 per cent to 45 per cent.
In order for a legal referendum to be held, the UK government must transfer the necessary power to their Scottish counterparts.
Johnson turned down Sturgeon’s latest request last month.
Truss was asked about Sturgeon’s call on independence during the second Conservative party membership hustings in Exeter.
Truss, who was born Paisley, described herself as a “child of the Union”. She said: “I really believe we are a family, and we’re better together.
“I think the best thing to do with Nicola Sturgeon is ignore her. I’m sorry, she’s an attention seeker, that’s what she is.”
She added that “we had the referendum in 2014. It was agreed it was once in a generation… I didn’t realise a generation was once every ten years ... we’ve got to call her out on that”.
She insisted “no, no, no” when asked about whether there would be another vote if she was prime minister.
Sturgeon has said that if the UK government continues to refuse a second independence vote, she will turn the next general election – due in 2024 – into a “de facto referendum”.