If you like the Harry Potter series, you might like
Happenstance Found, Books of Umber #1, by P.W. Catanese
A boy awakens, blindfolded, with no memory of even his name, but soon meets Lord Umber, an adventurer and inventor, who calls him Happenstance and tells him that he has a very important destiny--and a powerful enemy.
Gregor the Overlander, Underlander Chronicles #1, by Suzanne Collins
When eleven-year-old Gregor and his two-year-old sister are pulled into a strange underground world, they trigger an epic battle involving men, bats, rats, cockroaches, and spiders while on a quest foretold by ancient prophecy.
The Eternal Hourglass, Magickeepers #1, by Erica Kirov
Nick Rostov learns on his thirteenth birthday that he is descended from a powerful line of Russian Magickeepers, and that evil Shadowkeepers will stop at nothing to get an ancient relic that his grandfather gave him.
Theodosia and the Serpents of Chaos, by R.L. LaFevers
Twelve-year-old Theo uses arcane knowledge and her own special talent when she encounters two secret societies, one sworn to protect the world from ancient Egyptian magic and one planning to harness it to bring chaos to the world, both of which want a valuable artifact stolen from the London museum for which her parents work.
Savvy, by Ingrid Law
Recounts the adventures of Mibs Beaumont, whose thirteenth birthday has revealed her "savvy"--a magical power unique to each member of her family--just as her father is injured in a terrible accident.
The Chronicles of Narnia, by C.S. Lewis
A World without Heroes, Beyonders #1, by Brandon Mull
Fourteen-year-old Jason Walker is transported to a strange world called Lyrian, where he joins Rachel, who was also drawn there from our world, and a few rebels, to piece together the Word that can destroy the malicious wizard emperor, Surroth.
Fablehaven, by Brandon Mull
When Kendra and Seth go to stay at their grandparents' estate, they discover that it is a sanctuary for magical creatures and that a battle between good and evil is looming.
The Red Pyramid, Kane Chronicles #1, by Rick Riordan
After their father's research experiment at the British Museum unleashes the Egyptian god Set, Carter and Sadie Kane embark on a dangerous journey across the globe--a quest which brings them ever closer to the truth about their family, and their links to a secret order that has existed since the time of the pharaohs.
Elissa’s Quest, Phoenix Rising trilogy, by Erica F. Verillo
Thirteen-year-old Elissa knows nothing of her origins until her father comes and takes her to the Citadel of the evil Khan, in exchange for soldiers to protect the kingdom that will one day be hers, but upon discovering her power, she chooses to follow her own destiny.
The Book of Three, Prydain Chronicles, by Lloyd Alexander
Taran, Assistant Pig-Keeper to a famous oracular sow, sets out on a hazardous mission to save Prydain from the forces of evil.