Updated list of fastest fifties in T20 international cricket matches.
Presently Yuvraj Singh hold the record of fastest  half-century in 12 balls in T20 cricket career.

Fastest Fifties in T20

Player Team Balls Against Venue Date
Yuvraj Singh India 12 England Durban 19/09/2007
PR Stirling Ireland 17 Afghanistan Dubai (DSC) 24/03/2012
SJ Myburgh Netherlands 17 Ireland Sylhet 21/03/2014
DA Warner Australia 18 West Indies Sydney 23/02/2010
GJ Maxwel Australia 18 Pakistan Mirpur 23/03/2014
DA Warner Australia 19 South Africa Melbourne 11/1/2009
G Gambhir India 19 Sri Lanka Nagpur 9/12/2009
Mohammad Ashraful Bangladesh 20 West Indies Johannesburg 13/09/2007
Yuvraj Singh India 20 Australia Durban 22/09/2007
Yuvraj Singh India 20 Sri Lanka Mohali 12/12/2009

Updated Date: 23 March 2014

T20 Records
Most Runs Most Wickets Most Sixes
Highest Score Fastest Fifty Fastest Century
Most Fifties