Lastva Grbaljska's population is made up of 51.5% Serbs, which is also the second largest ethnic group in Montenegro, and 37.7% Montenegrins while other ethnicities make up only 10.8% of the village's population.
Serbs form a significant minority at 28.7%, followed by Bosniaks, Albanians and Croats. Montenegro is a multiethnic state in which no ethnic group forms a majority. Major ethnic groups include Montenegrins (/Crnogorci) and Serbs (/Srbi); others are Bosniaks (Bosnjaci), Albanians (Albanci  Shqiptaret) and Croats (Hrvati). The number of "Montenegrins" and "Serbs" fluctuates widely from census to census due to changes in how people perceive, experience, or choose to express, their identity and ethnic affiliation. 
