The visitors' victory in Sunday’s match at the Sylhet International Cricket Stadium, their biggest ever T20 win against the hosts, capped off a highly successful tour.
Bangladesh won the toss and sent the Lankans in, who scored 210 for 4.
The Tigers were all out in the 19th over making only 135 all out.
Summary score
Sri Lanka: 210/4 (Gunathilaka 42, Mendis 70, Perera 31, Tharanga 25, Shanaka 31*, Chandimal 2*; Jayed 1/45, Nazmul 0/28, Mahedi 0/25, Mustafizur 1/39, Saifuddin 1/46, Soumya 1/25)
Bangladesh: 135 in 18.4 overs (Tamim 29, Soumya 0, Mushfiqur 6, Mithun 5, Mahmudullah 41, Ariful 2, Saifuddin 20, Mahed 11, Mustafizur 8, Jayed 2, Nazmul 1*; Madushanka 2/23, Dananjaya 1/20, Shanaka 1/5, Thisara 0/33, Aponso 1/31, Udana 1/12, Gunathilaka 2/3)