Thanks everyone... I went through the requirements as stated on the websites of the top schools and I have this :
HBS : Internet-based Test of English as a Foreign Language (TOEFL iBT) or International English Language Testing System (IELTS) score from a test taken January 1, 2011 or later, is required for international applicants who attended a non-English-speaking undergraduate university.
Wharton : The Test of English as a Foreign Language (TOEFL) is required for all international applicants whose native language is not English. You may waive the TOEFL if you have earned an undergraduate degree or master's degree in an English-speaking country or from an institution in which English is the language of instruction; applicants must provide evidence to support the waiver.
Yale : You must submit a TOEFL, PTE Academic, or IELTS score if English is not the primary language of instruction at your degree-granting undergraduate or graduate institution. If English was the primary language of instruction at either institution, you do not need to submit a TOEFL, PTE Academic, or IELTS score or request a waiver of this requirement.
Stanford : If you have an undergraduate or graduate degree from a college or university where instruction was provided in English, you are exempt from taking the TOEFL, IELTS, or PTE.
All instruction must have been provided in English. You must take the TOEFL, IELTS, or PTE if some classes were taught in a language other than English.
Stanford goes a step further by providing examples :
The following examples illustrate whether or not you are required to take the TOEFL-IELTS-PTE:
1)Xiaogu from China went to Beijing for his undergraduate degree. Since the language of instruction was Mandarin, he is required to take the TOEFL-IELTS-PTE.
2)Ning from China got her undergraduate degree in London and is not required to take the TOEFL-IELTS-PTE because the language of instruction was English.
3)James from the United Kingdom went to Germany for his undergraduate degree and is required to take the TOEFL-IELTS-PTE (even though he is a native English speaker) because the language of instruction at the university was German.
4)Suki from Japan received her undergraduate degree from a US college where the language of instruction was all in English and is therefore not required to take the TOEFL-IELTS-PTE.
5)Fayza from Pakistan went to school in Islamabad where the language of instruction at her university was entirely in English, therefore she is not required to take the TOEFL-IELTS-PTE.
6)Chin from China went to Shanghai for her undergraduate degree but then went to Sydney for a graduate degree. Chin is not required to take the TOEFL-IELTS-PTE because the TOEFL-IELTS-PTE requirement is waived for any applicant with an undergraduate or graduate degree from a university at which the sole language of instruction is English.
I feel my situation is similar to that of Fayza (No.5).
The requirements as specified by each school are more or less worded the same, so I believe I am not required to take the TOEFL...
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