In the 2011 census, Porto Moniz had 2711 inhabitants, of those 1183 males and 1528 females, representing about 1% of the total regional population.

The population density of the municipality is 32.7 inhabitants per square kilometre and therefore attracted private investment in the residential tourism sector, which seeks nature and tranquillity.

The parish of Porto Moniz is the most populous, representing over the decades more than half the municipality's population with a total of 1668 inhabitants.

The second most populous parish is Seixal, which in 2011 represented 24.19% (656 inhabitants) of the population, followed by Ribeira da Janela with 8.41% (228 inhabitants) and Achadas da Cruz with 5.86% (159 inhabitants).