The 2003 Rio de Janeiro motorcycle Grand Prix was the twelfth round of the 2003 MotoGP Championship.

It took place on the weekend of 18–20 September 2003 at Autódromo Internacional Nelson Piquet.

The 125cc race marked the first Grand Prix motorcycle racing victory for a young Jorge Lorenzo.

Below are the standings for the top five riders and constructors after round twelve has concluded.

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