As of the 2021 census, Balashikha boasts a population of approximately 520,000 residents, making it the largest city in Moscow Oblast. This represents explosive growth over the last two decades, driven by both the 2015 administrative merger with Zheleznodorozhny and massive in-migration. Many people relocate from other parts of Russia to Balashikha for its relative affordability compared to Moscow, resulting in a relatively young, economically active demographic.
The ethnic composition is predominantly Russian. As a quintessential commuter city, a significant portion of the adult population travels into Moscow daily for employment, though local industries also support a robust workforce. The city has a highly educated population, reflecting the broader demographics of the Moscow metropolitan area.

