Wyoming ranked 50th in population in the US with an estimated total of 498,703 in 2002, an increase of 1% since 2000. Between 1990 and 2000, Wyoming's population grew from 453,588 to 493,782, an increase of 8.9%. The population is projected to reach 702,000 by 2005.

In 2000 the median age was 36.2. Persons under 18 years old accounted for 26.1% of the population while 11.7% were age 65 or older.

Wyoming ranks 49th in population density (5.1 persons per sq mi in 2000); only Alaska is more sparsely populated. However, during the 1970s Wyoming was the 3rd-fastest growing state; its population grew by 41%, from 332,416 at the 1970 census to 469,557 according to the 1980 census, largely from in-migration. The growth rate reversed during the 1980s, shrinking the population to 453,588 in 1990 (–3.4%).

Leading cities, all with populations of less than 100,000, are Cheyenne, Casper, and Laramie.