The 2013 Trans-Am Series was the 45th running of the Sports Car Club of America's Trans-Am Series.
The GGT class of the previous year was replaced by the TA3 class. The TA3 class was later broken into two groups TA3-International, based on SCCA GT2 rules, and TA3-American Muscle, based on NASA American Iron Racing class rules, with year and model restrictions.
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On December 21, 2012, Trans Am announced that the Ford Mustang would be added to the TA2 class, first introduced in 2010.