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Executive Leadership Team
Mr. Graham Lonie
Head of School
Graham Lonie joined TSI in June 2017 when our school commenced its renewal process. Since then, he has held several key positions to support the school's remarkable growth before becoming Head of School in 2025.
During his career, Mr. Graham has worked at schools in Australia, England and Thailand. He has a solid understanding of the local international school market which helps to guide the continued growth and redevelopment of our school. Mr. Graham feels very fortunate to be supported by an aspirational school Board with a strong vision and commitment for taking our school to new heights in the coming years.
Mr. Graham genuinely believes that TSI has a unique culture built on mutual respect and he is determined to work with our community to ensure that this remains as our community grows and diversifies.
In his role as Head of School, Mr. Graham works between TSI Bearing and TSI Wongwianyai Campuses. He values interactions with our students and their parents.
Ms. Marlie Human
Wongwianyai Primary School Principal
With remarkable growth continuing at TSI Wongwianyai Campus, Marlie Human was appointed to as the Primary School Principal position in January 2023.
With many years of experience teaching in international schools around the world and an in-depth understanding of the British Curriculum, Ms. Marlie first joined TSI as a classroom teacher in 2019. She was also a Key Stage Coordinator, SEN Coordinator and Deputy Principal.
Ms. Marlie holds a Bachelor of Education (Pre-School and Foundation Phase), majoring in Psychology with distinction. She also holds a Post Graduate Diploma in Special Educational Needs Support.
Ms. Marlie has a strong love of global citizenship and building inclusive classroom environments which cater for the specific needs of all children. She believes that every moment that a child is at school is a learning opportunity. She is dedicated to ensuring that one of our school’s main foundations is a positive community spirit shared by our learners, their parents and our teachers.
Ms. Michelle Crowley
Bearing Primary School Principal
Ms. Michelle’s greatest passion in education lies in seeing children learn through a personalised approach, using their own interests and skills to create a bespoke learning journey. She firmly believes that every child has unique potential and it the responsibility of educators to nurture and empower each child’s unique potential.
Prior to joining TSI in 2025, Ms. Michelle served as the founding principal of an international school in China. She has also been the principal of international schools in Egypt and Saudi Arabia.
Ms. Michelle is now working with TSI teachers, parents and children to build a vibrant, supportive and innovative ol community!
Mr. Adam Probert
Secondary School Principal
Originally from South Wales in the UK, Adam Probert has been an educator since 2004. His transition to leadership began in 2008 and since 2019 he has held senior leadership positions at international schools in Macau and China. Committed to lifelong learning, Mr. Adam has since completed his MBA in Leadership and Management and is currently achieving Chartered Teacher (Leadership) status.
At the heart of Mr. Adam’s educational philosophy is the principle of service - to students, to colleagues, and to the wider community. He believes in nurturing not just intellect, but also a spirit that leads to a love of learning that extends beyond the classroom. My leadership is guided by integrity, empathy, and a firm belief that education has the power to transform lives.
Mr. Adam believes that TSI students should not just just aim for academic success - they should also find joy, inspiration, and a strong sense of belonging every single day. He shares the same passion and is dedicated to ensuring that our secondary school is a place where every child flourishes.
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