ACI Diamond Bar is now Keystone Education
I am excited to announce that ACI Diamond Bar has a new name, Keystone Education.
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For more than 20 years, feedback from students and parents has driven us to innovate and excel. Recent overhauls to education and increasing competitiveness in our local schools have made early preparation more important than ever. At the same time, we recognize that every student is unique, each requiring a personalized plan for success. We are experts at...

Meet Our Director
If Diane Sartor could be summed up in one word, "passion" would be the best candidate...
Our Mission
At Keystone Education, we recognize that every student is unique, each requiring a personalized education plan to develop a strong learning foundation. And with over 20 years of experience, we at Keystone Education are the experts at customizing the academic rigor and fundamentals necessary to ensure Elementary, Middle, and High School students sustained success through college and beyond.
Our Latest News

Keystone's Official
SAT Study Guide
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6 Complete SAT Tests
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20+ Detailed Math Lessons
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Sample Essays Written by Students
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10+ Critical Reading Strategies
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13 Exclusive Grammar Lessons

Our New Location!
We moved to a brand new building with completely new classrooms equipped with Smartboard Technology.
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