Dahl's tale was the overall winner in The Nation's Favourite Children's Book poll organised by BBC1's Bookworm programme and Waterstone's bookshops, and his books took seven places in the under-16s' top 10.
More than 10,000 people voted by phoning the BBC poll or at Waterstone's branches. The top 10 from the over-16s' vote, which had no upper age limit, was a monument to what one observer called "the comfort factor" and adult nostalgia. Kenneth Grahame's The Wind in the Willows kicked off a list mainly composed of early 20th-century children's classics - The Lion, the Witch and the Wardrobe at number 2, Winnie-the-Pooh at number 3, The Secret Garden and Alice in Wonderland further down - with two Dahl titles sneaking in at numbers 8 and 10.
What is missing is any sense of what younger children are reading - there are no picture books in the under-16s top 10, unless you count Winnie-the-Pooh - or of what contemporary authors young adults are discovering now, rather than looking back on.
"The under-16s' Top 10 suggests the reading of eight to 12-year-olds before they have had time to become nostalgic. Perhaps it's this group that's most likely to take part in a poll of this nature," said Elizabeth Hammill, director of the forthcoming Centre for the Children's Book in Newcastle-upon-Tyne and a former children's bookseller. "But I'm not surprised at the amount of Dahl. He's got an uncanny ability to get into a child's mind - the part that has to do with dreams and nightmares. He's always sold well, although of course the success of Matilda may be linked to the film. I'm surprised that there's no Dick King-Smith on the list."
Mrs Hammill, who also co-ordinates a review magazine written by over-13s, believes the contemporary classics favoured by this group have slipped into the gap between the two polls. "It's possible that young people who would read The Iron Man by Ted Hughes may not think of entering a poll. There's an awful lot of classics - I think that's down to the comfort reading factor, or a big adult vote."
The winners were announced by Bookworm presenter Griff Rhys Jones on Monday. The programme, scheduled for last Sunday but cancelled because of the death of the Princess of Wales, will be repeated this Sunday.
An earlier survey of 25,000 Waterstone's customers found that adult Britons' favourite work was JRR Tolkien's The Lord of the Rings.
Under-16s' Top 10
1 Matilda (Roald Dahl)
2 Charlie and the Chocolate Factory (Roald Dahl)
3 The BFG (Roald Dahl)
4 Winnie-the-Pooh (A A Milne)
5 The Hobbit (J R R Tolkien)
6 James and The Giant Peach (Roald Dahl)
7 The Witches (Roald Dahl)
8 The Twits (Roald Dahl)
9 George's Marvellous Medicine (Roald Dahl)
10 Double Act (Jacqueline Wilson)
Over-16s' Top 10
1 The Wind in the Willows (Kenneth Grahame)
2 The Lion, The Witch and The Wardrobe (C S Lewis)
3 Winnie-the-Pooh (A A Milne)
4 The Hobbit (J R R Tolkien)
5 Swallows and Amazons (Arthur Ransome)
6 The Secret Garden (Frances Hodgson Burnett)
7 Alice in Wonderland (Lewis Carroll)
8 Charlie and the Chocolate Factory (Roald Dahl)
9 Little Women (Louisa M Alcott)
10 Matilda (Roald Dahl)