Mrs. Doa Demirsu-Doran, Principal, BSc, MBA

Welcome to Keystone International School, a dynamic, boutique school, in the heart of Toronto.

We strive to involve students in their own learning experience. Teachers are not lecturers but are facilitators in the classrooms. Our inquiry-based, holistic approach to education encourage students to take action and become life-long learners. We always remind students that every subject has a relation to the real world. Whenever we can get away from the classroom, we make sure to do that; it’s far more interesting to go check out some super structures to think the physics behind it, see live art pieces and discuss them at the museum, or play logic games to calculate probability for math class. In Economics or Business, we observe a product over time to understand the effects of demand and supply. All these experiments keep students interested and makes learning easier, fun and most importantly permanent.

At Keystone, we nurture our students to be well-rounded and intuitive individuals while challenging them to excel academically. Our culturally diverse environment prepares our students for the future when they will be collaborating with others at a global level.

Upper School

All staff and teachers at Keystone are committed to making a difference in our students’ lives. They are knowledgeable, creative, caring, inspirational and highly qualified. They know their students well and are able to devote their attention to their strengths and areas of potential growth. As such, they focus on delivering a program that inspires students to participate, reflect, think critically, analyze, create and excel academically.

Teachers create classrooms where students can feel a sense of belonging and develop programs that motivate students to investigate and  inspire learning.

Darlen Navarro, B.Eng, BSc, MMT
Darlen Navarro, B.Eng, BSc, MMT
Mrs. Navarro holds two undergraduate degrees, one in Telecommunications and Electronics Engineering and a Bachelor of Science in Applied Mathematics from York University, In addition, she holds a Master of Mathematics for Teachers through the CEMC at University of Waterloo. Also an Advanced Diploma in Business Administration and Accounting from Sheridan College.

She imparts applicable knowledge and problem solving techniques on her students in her mathematics classes. Her teaching experience includes topics like Differential Calculus, Numerical Mathematics and Linear Algebra, as well as International Baccalaureate and advanced mathematics and physics from Grade 9 to 12.

Stephanie Guerreiro, BA, B.Ed.
Stephanie Guerreiro, BA, B.Ed.
Ms. Guerreiro completed her Bachelors of Arts, History at Trent University and her Bachelors of Education from Queen’s University. She spent the first five years of her teaching career working with students in Nanjing, China where she was able to explore her love of travel and experiencing different cultures.

She loves working with students from international backgrounds as well as those from closer to home as they all have stories and experiences to share that make the world more colourful and fulfilling. Her favourite courses to teach are history and geography as they give everyone in the class a chance to broaden their world-views and learn about the world around them.

Radini Rajaratne, B.Sc.
Radini Rajaratne, B.Sc.
Ms. Rajaratne completed an Honours Bachelor of Science at the University of Toronto, where she studied Genetics and Psychology. She is currently pursuing a Masters in Education in Educational Leadership and Policy.

She began her teaching career through various volunteer positions, including teaching children English as a Second Language in Sri Lanka, teaching music at a local community school and hosting art workshops in Toronto. She is passionate about exposing students to the fun and intriguing side of the natural and social sciences whilst also teaching them skills that are essential in life. Ms. Rajaratne believes that education is a lifelong process, and it is through education that we find the tools and the knowledge to navigate through the ever-changing challenges of this world.

Ece Ozturk, BMath, BBA, MA(Hons)
Ece Ozturk, BMath, BBA, MA(Hons)
Ms. Ozturk has completed a Bachelor’s of Mathematics together with a Bachelor’s of Business Administration. She also holds a teaching certificate as well as a Master of Arts in Educational Administration and Supervision, which she completed with honours.
Ms. Ozturk is passionate to share her love for learning with her students. She wants to instill a natural curiosity in the minds of students so that they can find strategies to navigate today’s fast-paced world. She believes teaching to be the first step in making a difference in this world. Therefore, she wants to share her knowledge and experience with her students wherever she is.
Craig Telford, B.Sc., M.Ed
Craig Telford, B.Sc., M.Ed
Mr. Telford is originally from Gateshead, a small town located in the North-East of England. He holds a Masters of Education degree with a specialization in Biology, as well as a Bachelor of Science degree majoring in Physiology. He is also an ISSA (International Sports Science Association) certified Specialist in Fitness Nutrition. He has previously taught all homeroom subjects, as well as Science in England, Malaysia and Canada ranging from grades 6 to 12.

Mr Telford’s educational path has taken him on a journey through over 25 different countries, hundreds of different cultures and thousands of unique individuals who all had a lesson and story to tell. Through countless unique experiences Craig has witnessed that “sometimes it is the people no one can imagine anything of, who do the things no one can imagine” is ubiquitous.

Seemi Jamil, BA, MA
Seemi Jamil, BA, MA
Ms. Jamil is a trained family counsellor, she transferred her skills into teaching for the last seven years. She has a Bachelor of Arts from McMaster University in Sociology and Psychology, in addition to a Crisis Counselling certification, TESL certification and a teaching licensure from Washington D.C. Ms. Jamil has taught in England, Turkey, Egypt and Canada, combining her love for education and diversity as a third culture individual herself. She also has worked with diverse youth groups in Toronto in organizations striving to make education accessible to newcomers, refugees and communities of all socioeconomic backgrounds. Her interests include meditation and mindfulness, social justice, poetry, mental health, music from all over the world, psychology and trauma-informed educational approaches.
Taylor Berce, BA, MA
Taylor Berce, BA, MA
Mr. Berce holds a Bachelor’s of Arts from McGill University, where he studied geography, and a Master’s degree from York University, where he studied linguistics. His broad variety of experiences as an educator include working as a librarian at McGill’s cartography library in Montréal, teaching children in Guangzhou, China, and helping newcomers to Canada learn English in Toronto. Taylor sees learning a language as a holistic, lifelong process. Stemming from his Master’s research, he is particularly interested in analyzing the use of language in “real world” contexts and the linguistics sub-discipline of corpus linguistics.
Esra Perek, BEd
Esra Perek, BEd
Mme Perek has been teaching French since 2004 for different age groups and learning needs. Graduated from Istanbul University with double major in French Linguistics and Elementary Teaching. Esra believes that the main thing in learning a language is first to like it. To like it, a student has to get to know a few concepts like the culture and the country/countries that this language is spoken in. She also believes that every student has its own way to perceive the subject. Mme Perek is trying to penetrate this knowledge into her classes and teach accordingly. She’s on a mission to teach with patience and perseverance and make the learning possible for everyone.