The 28-year-old came out on top in an eight-man shortlist that included teammates Bruno Guimaraes and Kieran Trippier, Kepa Arrizabalaga, Erling Haaland, Kevin De Bruyne, Leandro Trossard and Granit Xhaka.
Almiron scored a joint-high six goals during the month of October and becomes the first Paraguayan since Roque Santa Cruz to win the award.
"I'm really, really happy at receiving this award," Almiron told NUFC TV.
"It's lovely on a personal note and a very nice moment for me to win something like this as a player, but it's all about the team."
Almiron has been in superb form for high-flying Newcastle United this season, scoring eight goals in 14 games overall.
The former Atalanta United forward also won the goal of the month award.
Elsewhere Magpies manager Eddie Howe won the best manager for October after guiding Newcastle to an unbeaten month which included five wins.
It is the fifth time Howe has won manager of the month award, with three of those coming while in charge of Bournemouth.
Howe beat Pep Guardiola and Mikel Arteta to October's award.
