If you like Molly Moon by Georgia Byng

If you like the Molly Moon series, you might also like to read:

The City of Ember by Jeanne Du Prau.
In the year 241, twelve-year-old Lina trades jobs on Assignment Day to be a Messenger to run to new places in her decaying but beloved city, perhaps even to glimpse Unknown Regions. The sequel, The People of Sparks, has just been published.

Gregor the Overlander by Suzanne Collins
Don't be turned off by the cover of this one! It's a great story of Gregor and his two-year-old sister. When they 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 Tale of Emily Windsnap by Liz Kessler
After finally convincing her mother that she should take swimming lessons, twelve-year-old Emily discovers a terrible and wonderful secret about herself that opens up a whole new world.

Sahara Special by Esme Raji Codell
Struggling with school and her feelings since her father left, Sahara gets a fresh start with a new and unique teacher who supports her writing talents and the individuality of each of her classmates.