"Do Somethin'" received generally favorable reviews from critics, and received comparisons to Gwen Stefani's 2004 single "What You Waiting For?". Although the single was not released in the United States, it charted on many of "Billboard"s component charts due to digital downloads, managing to reach number 100 on the "Billboard" Hot 100. It was also successful worldwide, reaching top ten positions in countries such as Australia, Denmark, Sweden and the United Kingdom. By the end of 2005, "Do Somethin'" was one of the best-selling singles in Australia and Belgium that year.