The Buet Board of Residence and Discipline has taken the decision based on the report of a probe panel formed the university to look into the gruesome murder.
A notice, signed by member secretary of the board and director of Buet's Directorate of Students' Welfare Prof Mizanur Rahman, was issued on Thursday night.
Of those expelled, 25 are charge-sheeted accused in the Buet student murder case.
Besides, six other students have been punished for different terms for breaching discipline, the notice said.
Abrar Fahad, 21, a second-year student of electrical and electronic engineering of Buet, was beaten to death reportedly by BCL leaders at Sher-e-Bangla Hall of the university.
He was found dead on the staircase of the hall in the early hours of October 7 after he was taken to the room No-2011 around 8pm on October 6 and beaten mercilessly.
On November 13, the Detective Branch (DB) of Dhaka Metropolitan Police (DMP) pressed charges against 25 people in the Buet student killing case.
Those expelled are Mehedi Hassan Rasel, Muhtasim Fuad, Anik Sarker, Mehedi Hasan Robein, Ifti Mosharraf Shakal, Moniruzzaman Monir, Meftahul Islam Zion, Mazedur Rahman, Muzahidur Rahman, Khandaker Tabakhkharul Islam Tanvir, Hossain Mohammad Toha, Md Akash Hossain, Md Shamim Billah, ASM Nazmus Sadat, Ehtesamul Rabbi Tanim, Morshed Amartya Islam, Moaz Abu Huraira, Muntasir Al Jemi, Amit Saha, Muztaba Rafid, Ishtiaq Ahmed Munna, Shamsul Arefin, Mizanur Rahman, SM Mahmud, Morshed-uz-Jaman Mondal and Ashiqul Islam.