The 57th and 2013 edition of the book says the City Montessori School (CMS) in Lucknow had a record enrolment of 39,437 pupils on Aug 9, 2010, for the 2010-11 academic year.
School authorities told IANS that the number of pupils now stood at 45,000-plus.
The entry in the Guinness, which documents the world’s most unique and selective records, has enthused the students and staff.
“We are very happy that not only our size but also our philosophy of world peace is being recognized at a global level,” school founder Jagdish Gandhi told IANS.
Tanmay Tiwari, a Class 12 student on one of the 20 branches the school operates in the city, is equally estatic.
He said studying in one of the school campuses was an “enriching experience” which “mattered a lot in the transition” in his persona.
Principal Vera Hazela says her association with the school has been a “great one”.
Talking of the exposure the school gives to its students, she said the school holds 32 educational international events every year.
School spokesperson Rishi Khann said the management, staff and students were overjoyed over the Guinness recognition.
The school was founded in 1959 by Jagdish Gandhi and his wife Bharti Gandhi in a rented premises with just five students and a borrowed capital of Rs.300.
The school was also awarded the prestigious Unesco Prize for Peace Education in 2002, becoming the only school worldwide ever to receive this honour.