The composer, whose hits include The Phantom of the Opera, Cats and Evita, is charging between £25-£95 for his latest London musical School of Rock.
The average ticket price for a West End musical in 2016 was £49.28 - up almost 6% on the previous year.
"Theatre is incredibly labour intensive," he said.
"On the whole, the prices of West End theatre are incredibly reasonable considering the cost of what it is to put something on."
Last year, Lord Lloyd-Webber revealed that the physical running costs for one of his theatres was £38,000 per week.
On top of that, there are the costs of staging the production itself. The Financial Times estimated that the total weekly costs of a top musical are £150,000-£250,000.
And most musicals spend years in development. The Stage estimated that the budget for the Broadway production of Groundhog Day - not a Lloyd Webber production - was $18m (£14m).
Elsewhere in the West End, Harry Potter and the Cursed Child has a top price of £140, while Hamilton has £200 premium tickets for when it officially moves to London in December.
The topic of ticket costs often arouses strong feelings. Actor Andrew Scott recently called the high prices "disgusting", while last year, Mark Gatiss said theatre was an "exclusive club for rich white people".
Lord Lloyd-Webber also pointed out that UK theatre tickets include 20% VAT - while tickets in the US are not taxed.
The composer was speaking to BBC arts editor Will Gompertz's Heat Map programme on BBC 5 live, and also said he is currently looking for an idea for a new musical "rather desperately".
"I must say I don't think I've ever felt more excited about musicals," he said. "I feel like I'm back when I'm started."
That is partly down to a resurgence of the genre in the US with hit shows like Hamilton, Dear Evan Hansen and Come From Away. In comparison, the UK is coming up with few successful original musicals.
"Everything is so vibrant in America, which has always really been the home of musicals. Fourteen new musicals this year. I mean, fourteen. This year we've only had two in Britain."
Lord Lloyd-Webber made his name in the 1970s collaborating with lyricist Tim Rice on shows like Jesus Christ Superstar, Joseph and the Amazing Technicolor Dreamcoat and Evita.
The pair haven't worked together on a full show since - but Lord Lloyd-Webber hasn't ruled out a reunion.
"It's a shame in a way we didn't go on writing together but we are very different people in several ways," he said.
"Never say never, but Tim has written the lyrics to the most successful musical currently playing in the world, which is The Lion King. He's got Beauty and the Beast, he's got Aladdin.
"He doesn't exactly need to write. If he wanted to do something, if he wanted to come to me with an idea... I think it would have to be him wanting to do the idea.
"If I went to him and said, 'Look, shall we do this?' I don't think he'd want to do that."
Lord Lloyd-Webber was speaking ahead of receiving an outstanding contribution honour at the South Bank Sky Arts Awards on Sunday.
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Andrew Lloyd Webber has said ticket prices for West End shows are "incredibly reasonable" given the cost of bringing a production to the stage.