The name Portfield is thought by some to be a corruption of Poor Field (a field which all could use) but in the late 13th century it was referred to as Portefelde and has also been known as le Portefeld, Poertefyld, Portfilld, le Portffeld, Portfeild, Porfeild and Portfild.

B G Charles in his seminal work on Pembrokeshire place names believed its meaning was ‘Open field belonging to the town (of Haverfordwest)’ v. port, field