The program is part of a $61 million investment to raise test scores. Apollo 20 receives some of its funding from the Bill and Melinda Gates foundation and is now in its third year.
It was launched at four high schools and five middle schools in 2010 and was it expanded to include 11 elementary schools.
The strategies used at the schools have been identified by Harvard University's Education Innovation Laboratory. They include more instructional time, use of laptops and other technology to drive instruction and in-school tutoring.
"A lot of students come in at a lower grade level, above grade level. We had special needs students and we got them on grade level and then above that," said tutor Ruben Vasquez.
While Apollo middle and high school students begin school today, the first day of school for Apollo elementary and all other HISD schools is next Monday, August 27.