Morgan returned to the side after being rested for the second match in Dubai which England won by three runs. Also included in the side are Moeen Ali and Chris Jordan.
England, who have an unbeatable 2-0 lead, left out Liam Plunkett, Alex Hales and Stephen Parry.
Pakistan made three changes bringing in Mohammad Irfan, Aamer Yamin and Mohammad Rizwan in place of Wahab Riaz, Sohaib Maqsood and Sarfraz Ahmed.
The 25-year-old Yamin is making his Twenty20 debut.
Teams:
Pakistan: Shahid Afridi (captain), Mohammad Hafeez, Rafatullah Mohmand, Ahmed Shehzad, Umar Akmal, Shoaib Malik, Mohammad Rizwan, Anwar Ali, Sohail Tanvir, Mohammad Irfan, Aamer Yamin
England: Eoin Morgan (capt), Jos Buttler, Moeen Ali, Sam Billings, Chris Woakes, Moeen Ali, James Vince, Adil Rashid, Jason Roy, David Willey, Chris Jordan
Umpires: Ahmed Shahab (PAK) and Ahsan Raza (PAK)
Tv umpire: Shozab Raza (PAK)
Match referee: Ranjan Madugalle (SRI)