To Kill a Mockingbird and The Hunger Games have some similarities. They are both set in a small town. The characters know little of the world beyond their town. In To Kill a Mockingbird, the world outside of Maycomb isn't even discussed. While Katniss does venture into the world outside District 12 in The Hunger Games, she is certainly unprepared for the differences she will see.
Both characters are young children. Scout is a few years younger than Katniss, but both main characters share the innocence and inexperience of youth. Both characters are also faced with the harsh realities of life. They are forced to grow up and find the strength to face difficult situations.
Both stories deal with great injustice. Katniss is set to face this injustice herself while Scout must look on at the injustice done to another. Both are living in a world with unfair legal systems and corrupt governments. They each experience some form of persecution and witness great injustice both to themselves and to others.
They had a similar setting which was that they were in a poor economy trying to get by in life. To kill a mocking bird the Great depression was going on and in the Hunger games they are ruled by a dictator and the main character lives in one of the worst districts.