5 July 2010, rated PG
You probably won't have seen any of the film's young actors before, although they've all been in other movies or TV shows.
The adults are played by some fairly famous actors. Pierce Brosnan, who was James Bond before Daniel Craig, plays Chiron the Centaur.
Steve Coogan, who was Octavius in the Night at the Museum movies, plays Hades, God of the Underworld.
And Sean Bean, who was Boromir in the Lord of the Rings films, plays Zeus.
Percy Jackson thinks he's just a normal teenager who's dyslexic living in New York City. But he soon discovers he's the son of the Greek god Poseidon, which is why he has so much trouble reading in the human world.
A lightning bolt belonging to Zeus, the God of all Gods, goes missing and he blames Percy. It means Percy and his family are in danger, and his mum ends up getting kidnapped by Hades.
Percy has to go and stay at a demigod training camp called Camp Half Blood. After learning how to use his powers, he goes off with fellow demigod Annabeth (daughter of the Goddess Athena) and his satyr protector Grover to clear his name, rescue his mother and find Zeus' lightning bolt.
The film has great action scenes and the special effects are really fab!
The DVD has lots of extra bonus behind-the-scenes stuff inside Camp Half Blood. It also has interviews with the director, and stars of the movie, Logan Lerman, Brandon T. Jackson. You get to hear about how they had to learn to sword fight against each other!
We loved Chiron the Centaur - he looks so realistic! And Grover has the funniest lines.
Any weak bits?
It's not that clear why Percy is accused of stealing the lightning bolt in the first place. And towards the end the plot gets a bit muddled.
It's also a bit strange that he suddenly became a good fighter without much training- but he is a demigod after all!
Hit or miss?
There are loads of similarities with Harry Potter - the main characters are two boys and a girl, it's full of magical powers and there are loads of fight scenes against the baddies.
Instead of Hogwarts there's a secret training camp called Camp Half Blood (sound familiar?!).
Let us know what you thought of the DVD using the form at the top right hand side!
"I've read all the Percy Jackson books but the first one is the best and the film is fantastic! I am hoping the other books are made into films as well."
Emily, 10, Berkshire, England
"The first time I watched it was on DVD and it was amazing! I now wish that I'd seen it in the cinema."
Amy, 11, Hertfordshire, England
"Percy Jackson is very good, it has a lot of fighting scenes which is good. I rated it 9/10!"
Zeba, 10, Birmingham, England
"Great film. Not as great as my high expectations because it was slightly confusing. Overall, amazing film!"
Narmeen, 13, London, England
"It was really good and different."
Sophie, 9, Kent, England
"This movie is far by the best! The books are brilliant as well!"
Amy, 12, North Lanarkshire, Scotland
"This movie was one of the best I have ever seen. 9.5/10"
Josh, 10, Tauranga, New Zealand
"I think this film was really good and different. I give it 8/10."
Sadie, 12, Staffordshire, England
"I thought the movie was good, so good that I read the book. That's when I found out that the movie was really different from the book."
Niamh, 10, East Sussex, England
"It was fab. I really enjoyed it on DVD."
Lucy, 9, Cardiff, Wales
"All of it was funny and it was so interesting that it is my favourite film."
Georgia, 7, Sheffield, England
"It is the best movie ever. Every part is top class!"
Dan, 11, Swansea, Wales
"It is so good. The extra bits are really cool as well!"
Francesca, 9, London, England
"It was really good to watch. It was interesting and enjoyable. Go Percy!"
Frankie, 13, Essex, England
"One of the best movies I've ever watched! I found it really engaging and it was a really good film!"
Ameena, 11, Berkshire, England
"I think that this movie is brilliant! Both thrilling and funny!"
Libby, 10, West Sussex, England
"I really liked the movie, it was great."
Alisha, 10, Lancashire, England
"I think Percy Jackson and the Lightning Thief is an amazing film. My brother went to see it twice because it was that good! My fave character is the girl teenager who is a demi-god too."
Rebekah, 11, Edinburgh, Scotland
"It was the best film I have seen. I dressed up as him. I bought the book because if the film was good, the book must be good and it is."
Christopher, 10, Neath Port Talbot, Wales
"This film is brilliant!"
Jessica, 12, London, England
"Bad and sad!"
Laura, 8, London, England
"It's the best film ever, ever made. It's even better than Avatar."
Oscar, 9, England
"Absolutely good and it is the best film I have ever seen."
Reece, 9, Kent, England
"I think it is so cool so I give it a 10/10. SUPER!"
Jenny, 12, Drenthe, Netherlands
"Top film of the year! Five out of five! Lost in the world of Percy Jackson! The books are even better though."
Lauren, 9, London, England
"I think that the film is awesome."
Natalia, 9, Wakefield, England
"This is very good indeed."
Tommy, 9, London, England
"I think this was very good. I haven't read the book, but my brother says they missed some stuff out and it was confusing how he came from being not very clever to an amazing fighter. It was muddled at the end. However, the actress who played Anabeth and the actor who played Percy were both great! It was also very exciting! A GREAT FILM!!"
Ellie, 12, Hertfordshire, England
Saran, 11, Belfast, N. Ireland
"I thought the film was very good, although I like the books better. Rating 4 out of 5!"
Caitlin, 10, London, England
"It is cool and scary. There are no such thing as sea monsters."
Domingo, 7, Essex, England
"It is great, I've seen it and all the action scenes are amazing!"
Courtney, 11, Yorkshire, England
"I have seen Percy Jackson and the Lightning Thief and it is pretty scary! Especially the bit when Medusa is hanging around them!"
Max, 8, Peterborough, England
"When I saw the trailer, I knew that it was going to be great and it was!"
Cerys, 11, Glasgow, Scotland
"The best film and book ever! So excited for the second one coming out in 2012!"
Beatrice, 10, London, England
"I think the film was very good but I felt there were parts missing that were in the book. Overall though, a privilege to watch!"
Nerissa, 14, Southampton, England
"I think Percy Jackson is a fantastic film and I give it a 10/10. I'd definitely recommend it!"
Faye, 10, Manchester, England
"Best film ever, no doubt about it. I'm a fan of the film, five stars."
Angus, 10, Oxfordshire, England
"The special effects were amazing and when they were fighting it looked so real. I loved every second of it!"
Alex, 11, Belfast, N. Ireland
"I think the film is great! It is very interesting and it also helps with my ancient history."
Kelly, 10, London, England
"I think the film is really good and you should definitely go and see it."
Grace, 10, Zurich, Switzerland
"I read the books and although the film is good, it doesn't follow the novel. Annabeth is supposed to have blonde hair!"
Rachel, 14, Chester, England
"I have just watched it and I would give it 10/10. I still think the books are better."
Ellisah, 8, Lancashire, England
"Although the film is nothing like the book, I love it!"
Millie, 10, Hertfordshire, England
"Overall, it was good but they missed out parts."
Ansh, 12, Berkshire, England
"AMAZING! Percy Jackson is adventurous, funny and exciting. It is a 5 star film."
Ben, 10, Glasgow, Scotland
"It is one of the most amazing films."
Ben, 10, Essex, England
"I thought it was really good! I love the books more, even though the film was amazing. I rate this film 8 out of 10!"
Sulaiman, 10, London, England
"It was so good, I loved it!"
Tom, 12, London, England
"The most amazing film I have ever seen. Brilliant!"
Chloe, 13, Stoke-on-Trent, England
"The film was quite good but it was nothing like the book. If you didn't know the name of the film you could have thought it was a different story all together."
Lillian, 9, County Londonderry, N. Ireland
"I loved the film because I am such a Greek fan! 5 stars in my opinion."
Louise, 11, London, England
"This film is truly amazing! It has a meaning to it, unlike many other movies and is also quite educational. It's a must see film of 2010. Rating: 5/5."
Rebecca, 12, Lancashire, England
"A brilliant movie but I would give it a 12 rating."
Tom, 10, Glasgow, Scotland
"The plot was all wrong because the writers changed the main key points in the plot. Percy doesn't find out that he is the son of Poseidon straight away - that is revealed during the capture the flag game. I'm sorry, but the writers messed with the plot way too much. 3/5."
Guramrit, 12, Glasgow, Scotland
"Amazing books and an amazing film. I've watched this film at least three times."
Stephanie, 12, Glasgow, Scotland
"We read the book in school, then we saw it at the cinema. Although the film is nothing like the book, I still love it!"
Chloe, 10, Cornwall, England
"I think the film is excellent, buy it if you can."
Albert, 11, Essex, England
"This is a legendary DVD. A must for all action-packed people! 10/10!"
Alex, 12, Coventry, England
"The books are so much better! The film gets all of it wrong! They might as well have changed the name, most of the plot was completely different! But they are amazing books!"
Lauren, 14, Devon, England
"I think this is an amazing film, as there are special powers in this film that couldn't be brought to life. I believe it is a great film. I rate it 5 stars."
Jamie, 11, London, England
"I saw the movie in the cinema and thought on the way out, I am getting that when it comes out on DVD. Now it's out. 10/10!"
Patrick, 12, Glasgow, Scotland