Ellerslie, comprising the statistical areas of Ellerslie Central, Ellerslie West, Ellerslie East and Ellerslie South, had a population of 9,186 at the 2018 New Zealand census, an increase of 456 people (5.2%) since the 2013 census, and an increase of 1,149 people (14.3%) since the 2006 census. There were 3,174 households. There were 4,467 males and 4,722 females, giving a sex ratio of 0.95 males per female, with 1,695 people (18.5%) aged under 15 years, 1,926 (21.0%) aged 15 to 29, 4,566 (49.7%) aged 30 to 64, and 999 (10.9%) aged 65 or older.