Pakistan, who had lost their first two matches, reached 139 for six from their 20 overs, with Javeria Khan unbeaten on 74 of 52 balls.
Teenager Lucy O’Reilly took an impressive three for 19 but Pakistan’s total proved more than enough as Ireland could only manage 101 for nine.
Only Clare Shillington (27) and Isobel Joyce (30) - sister of former Ireland and England international Ed - reached double figures for Ireland, who lost heavily to Australia in their first match.