[en] The techniques developed for derivation of the light-cone expansion in scalar theories for its application to nonscalar, especially gauge theories are generalized. For this reason the smallness of the remainder is proved in an arbitrary renormalizable theory, provided an infrared regularization is present. The structure of the expansion and the arising light-cone operators are derived. It turns out, that the light-cone expansion in theories involving vector-fields (gauge theories) contains all powers of the vector-field operator. In this case the coefficient functions are not independent due to the gauge invariance. It is shown that with the help of the known solutions of the Ward- identities one can get a light-cone expansion with a finite number of operators and with idependent coefficient functions. This expansion is gauge invariant