Reza, 26, replaced paceman Nazmul Hossain, who was part of a Bangladesh Twenty20 squad that toured Europe last month.
"We included Reza for Nazmul as we needed to strengthen our batting," chief selector Akram Khan said.
"Hopefully his inclusion will give our batting depth, something which we were lacking on our recent tours."
Bangladesh whitewashed Ireland 3-0 in July but ended the tour on a sour note, losing to both Scotland and the Netherlands.
The Twenty20 World Cup will be held in Sri Lanka from September 18-October 7.
Squad: Mushfiqur Rahim (captain), Mahmudullah, Tamim Iqbal, Zunaed Siddique, Jahirul Islam, Mohammad Ashraful, Shakib Al Hasan, Nasir Hossain, Abdur Razzak, Elias Sunny, Mashrafe Mortaza, Farhad Reza, Shafiul Islam, Ziaur Rahman, Abul Hasan