  We investigate the tree-level S-matrix in gauge theories and open superstring
theory with several soft particles. We show that scattering amplitudes with two
or three soft gluons of non-identical helicities behave universally in the
limit, with multi-soft factors which are not the product of individual soft
gluon factors. The results are obtained from the BCFW recursion relations in
four dimensions, and further extended to arbitrary dimensions using the CHY
formula. We also find new soft theorems for double soft limits of scalars and
fermions in N=4 and pure N=2 SYM. Finally, we show that the double-soft-scalar
theorems can be extended to open superstring theory without receiving any
alpha' corrections.
