The 2003 Atlantic hurricane season was an active Atlantic hurricane season with tropical activity before and after the official bounds of the season – the first such occurrence in 50 years. The season produced 21 tropical cyclones, of which 16 developed into named storms; seven cyclones attained hurricane status, of which three reached major hurricane status. With sixteen storms, the season was tied for the sixth most active Atlantic hurricane season on record. The strongest hurricane of the season was Hurricane Isabel, which reached Category 5 status on the Saffir-Simpson Hurricane Scale northeast of the Lesser Antilles; Isabel later struck North Carolina as a Category 2 hurricane, causing $3.6 billion in damage (2003 USD, $4.04 billion 2007 USD) and a total of 51 deaths across the Mid-Atlantic region of the United States.

The season began with Subtropical Storm Ana on April 20, prior to the official start of the season; the bounds of the season are from June 1 to November 30, which conventionally delimit the period of each year when most tropical cyclones form in the Atlantic basin. In early September, Hurricane Fabian struck Bermuda as a Category 3 hurricane, where it was the worst hurricane since 1926; on the island it caused four deaths and $300 million in damage (2003 USD, $336 million 2007 USD). Hurricane Juan caused considerable destruction to Nova Scotia, particularly Halifax, as a Category 2 hurricane, the first hurricane of significant strength to hit the province since 1893. Additionally, hurricanes Claudette and Erika struck Texas and Tamaulipas, respectively, as a minimal hurricane.