We prepare students for an ever-changing future.
This year, Principia celebrates 125 years of progress. Serving children from infancy through grade 12, Principia School is a student-centered, future-focused coeducational day and boarding school grounded on the teachings of Christian Science. Creativity, critical thinking, and character growth are at the core of our college preparatory program. We welcome students of diverse faiths who value scholarship and are eager to grow in character, embrace opportunity, and pursue excellence.
Principia’s Reggio Emilia-inspired Early Childhood programs help young children—and their parents—take those important first steps on the road to lifelong learning and growth.
A strong and happy start paves the way for lifelong learning, developing new skills, and making discoveries.
From pre-algebra to PE, from intramural sports to student-planned dances, our holistic approach helps students develop habits of critical thinking and self-government.
From building a rocket car in our IDEA lab to starting a small business, upper schoolers put their understanding into practice, developing as thoughtful leaders, skilled communicators, and creative problem solvers.
We provide an education that builds character and hones skills for the betterment of humanity.
Best Christian High School
Best High School for the Arts
Best Private K–12 School
in St. Louis Area
Best Boarding High School
How We Rank
Niche is the nation’s leading online school review website. The 2023 Best Schools in America ranking is based on rigorous analysis of key statistics and millions of reviews from students and parents. Ranking factors include SAT/ACT scores, the quality of colleges that students consider, student-teacher ratio, private school ratings, and additional data sourced from the U.S. Department of Education.
"The teachers here truly want to see every student succeed, and I appreciate how they make the effort to provide as much support as possible to meet our needs.”
"I think it's amazing that it's a hands-on learning experience and not just sitting in a classroom all day. We get real-world experiences. Another aspect that I love is the environment. . . . I get to bond with my own class and others so that it's like one big community.”
"I like Principia because it has big playgrounds. The teachers are very kind and loving. I love my friends. Everyone at the school is happy and kind."
“What I love most about being at Principia is how we do not solely focus on academics. Here we focus on looking at the ‘whole man.’ We strive to show athleticism, emotional support, intelligence, social involvement, and having a spiritual mindset.”
“When you're at Principia, the first thing you always notice is how welcoming people are. There is not a day that goes by that I don't feel loved or supported. That's just how Principia shows its love back to you.”
Through hands-on projects such as creating a business and pitching ideas to a live “shark tank” of local experts, Principia offers unique opportunities for Middle and Upper School students to stoke their entrepreneurial curiosity and build skills.
The School’s annual Impact Challenge supports the United Nations’ Sustainable Development Goals, including the elimination of hunger and poverty, education for all, and clean energy, through student projects, classroom work, and community service initiatives at all levels.
Students at all levels explore the Bible through a variety of lessons and activities. Principia Bible classes are designed to enable students to develop a knowledge and love of the Scriptures while recognizing their relevance to society today. Upper School students have opportunities to take advanced classes with corresponding curriculum- based trips to Israel, the Holy Land, and Greece.
Officially dubbed the “IDEA Labs,” our two innovative STEM-focused SMART® Labs offer a space for exploration and experimentation for all K–12 students.
Our beautiful 360-acre campus features more than 100 acres of diverse habitats and outdoor learning spaces including fields, meadows, forest, ponds, and greenspace. Students at all levels focus on sustainability and experiential learning, bringing academic concepts to life in an outdoor environment.
The Challenge Course for students from kindergarten to Upper School is designed to move participants beyond personal limitations and develop their communication, problem solving, and collaboration skills. The course offers both low- and high-ropes areas and a rock-climbing wall.
Principia Adventure is a Middle School program that focuses on developing skills in the areas of leadership, collaboration, selfless service, seeking out challenge, and self-awareness. Students develop these attributes through outdoor, experiential opportunities such as rock climbing, fire building, backpacking, canoeing, orienteering, tracking, lashing, biking, and shelter building on our expansive campus and Challenge Course.
All Seniors develop and complete a Senior Project. The work culminates in a three-week capstone project in which students delve into a topic of personal interest that incorporates elements of service. Senior projects are a natural outcome of a Principia education and demand careful planning, self-discipline, and follow-through, and include a formal public presentation about the experience. Whether they decide to pursue a new interest or deepen an existing skill, these hands-on experiences provide an opportunity for students to learn through in-depth exploration.
A thematic, grade-specific Signature Experience builds upon the Upper School’s core curriculum, offering additional opportunities for students to develop future-ready skills and deep connections in their learning. Throughout the academic year, each Upper School grade level is immersed in classes, projects, and activities that relate to the year-long theme. These real-world experiences allow for the transfer of skills beyond the classroom. Students tackle challenges and contribute to the betterment of humanity through Outward Bound Character Trips/Leadership Retreat, Urban Experience, and the Impact Challenge, and more.
At Principia, you’ll get your hands dirty, test your theories, and put your understanding into practice.