Arbor Montessori School
At Arbor, we have a beautifully diverse community. We believe that each family is unique and that every family is welcome here. It’s important that children have a chance to celebrate their own families, including everything from culture and heritage to structure and members, and beyond. It’s also just as important for children to learn about all types of families, and come to understand that the only universal definition of a family is love. When we celebrate ourselves and others, we are creating an inclusive, welcoming community.
Arbor Montessori was founded in 1993 by Mary O’Brien with a clear and enduring purpose: to educate each child as a whole, unique person. What began with just eight elementary students on two acres of farmland on the Sammamish Plateau quickly grew into a thriving Montessori community rooted in respect, compassion, and authentic Montessori practice. From the beginning, Arbor has been family-owned and guided by the belief that children learn best in a peaceful, inclusive environment that honors curiosity, independence, collaboration, and a deep love of learning.
Mary’s journey with Montessori began in 1989, when she witnessed the focus, confidence, and joy young children displayed in a Montessori classroom. Inspired, she pursued formal Montessori training and opened Arbor Montessori School to extend this approach into the elementary years. Mary led Arbor as Head of School from 1993 to 2013, laying a strong foundation of educational excellence, human values, and community care. Leadership later passed to her son, Sean O’Brien, a credentialed Montessori educator and administrator, who served as Head of School until 2022, when Nicole Champoux became Head of School.
Arbor now serves up to 175 students from 15 months through sixth grade and remains grounded in its founding values. More than 30 years later, Arbor continues to grow with intention—guided by extraordinary educators, supported by engaged families, and dedicated to nurturing capable, compassionate, and confident children. Today, there are three schools in the Arbor family: Issaquah Montessori, Mt. Si Arbor in North Bend, and Arbor in Sammamish.
There isn’t a better Montessori school in the area. We have experience having our children in the program from infant through primary so far and have only felt lucky to be part of such a wonderful community of educators and administrators. The educators are passionate about care for the children and their Montessori based learning approach is an organic way for the children to learn per their individual needs. I was so impressed when my preschooler was reading at advanced levels so quickly and more importantly had great confidence in his ability to learn new concepts. The administrative staff is exception as well, having a hands on approach with families, with clearly great love and passion for the work they do and the families they are supporting. This is a wonderful community to be a part of and we highly recommend it.
