It's hard with so much other content out there like you-tube video's, TV, movies, computer games. Books just don't have the same draw.
My DS17 wasn't very interested in reading fiction in K-2nd. He read a ton of non-fiction. We had (and still do) tons of books about animals, dragons, whatever you name it. The text within many of these books are a lot harder than most fiction for this age. Keep in mind that a lot of early readers fiction books are honestly not that interesting & very predictable and twee.
And as other parents suggested. I read to my son every night before bedtime a chapter at a time. Good children's literature that was above his reading level. Sharing the enjoyment of a good story helped. What you don't want to do is make reading a chore or something he only does for homework and make him hate it at this age.
Good Luck.
