Chasing a target of 194, the hosts completed the task with 37 balls to spare.
Earlier, Ireland opted to bat and posted 193 for 6 in their 50 overs. Amy Hunter top-scored with a steady 68 off 88 balls, supported by Orla Prendergast (37) and Laura Delany (33). For Bangladesh, Sultana Khatun was the pick of the bowlers, claiming 2 for 32, while Nahida Akter and Shorna Akter chipped in with a wicket each.
In response, Bangladesh had a shaky start, losing opener Murshida Khatun early for 6. However, Fargana Hoque (50 off 89) and Sharmin Akhter (43 off 63) steadied the innings with a solid partnership. Captain Nigar Sultana added impetus with a brisk 40 off 39 balls, including four boundaries and a six.
Sobhana Mostary (16) and Shorna Akter, unbeaten on 29 off 29 balls, ensured a smooth finish, sealing the win with ease.
For Ireland, Laura Delany led the bowling effort with two wickets, but it wasn't enough to stop a well-rounded performance from Bangladesh.
The final match of the series will offer Ireland a chance to salvage some pride, while Bangladesh looks to complete a clean sweep.