The Primary School Programme at The Lexicon International School comprises of grades 1 to 5.

In these grades, the school follows a curriculum by drawing on teaching programme of CBSE  (Central Board of State Education).
Teaching and learning at The Lexicon International School is designed to be an enjoyable experience for children, thus making them want to come to school even when they don't have to. By increasing student interest, by making learning fun but meaningful, we lay the foundation for developing a lifelong interest in learning. Thus, children are developed and oriented with a readiness to successfully enter the middle school and beyond.

In these grades 1 to 5, Hindi is offered as the second language. Students will begin learning French as a third language from grade 5.

In grades 1 - 5, the focus is on encouraging inquiry, exploration and on inculcating growing confidence in key learning skills - reading, writing, listening, speaking, information technology capability, problem-solving, management skills, observation and measurement. Children are encouraged to speak and perform at assemblies, concerts, drama productions, and so gain confidence in their ability to communicate to a wider audience. Children are also encouraged to take part in various competitions and other celebrations organised by the school regularly. They are also encouraged to take part in field trips and community service.