GAlib - A C++ library of genetic algorithm objects.
jaga - Java Genetic Algorithm Package. http://cs.felk.cvut.cz/~koutnij/studium/jaga/jaga.html
Simple GA code in C (for Windows and Linux)
Single-objective GA code in C (for Windows and Linux)
Multi-objective NSGA-II code in C
http://www.iitk.ac.in/kangal/codes.shtml
GEATbx - The Genetic and Evolutionary Algorithm Toolbox for Matlab