The following lists the number one best-selling singles in Canada in 2003 which was published in Billboard magazine under the Hits of the World section.^[1] Only songs released as physical singles qualified for this chart during this time. During this period, the singles market in Canada was very limited in both scope and availability and, in many cases, these songs received little or no radio support. For tracks other than those by American Idol or Canadian Idol winners, sales were likely to be less than 1,000 per week. Nevertheless, this was the only singles chart Canadians had until June 2007, when the Canadian Hot 100 was released to the public. It also lists other big hits in the sales chart.

Note that Billboard publishes charts with an issue date approximately 7–10 days in advance.