  We study the impact of additional beyond-the-Standard Model (BSM) fermions,
charged under the Standard Model (SM) $SU(2)_L \otimes U(1)_Y$ gauge group, on
the electroweak phase transition (EWPT) in a 2-Higgs-Doublet-Model (2HDM) of
type II. We find that the strength of the EWPT can be enhanced by about 40%
compared to the default 2HDM. Therefore, additional light fermions are a useful
tool to weaken the tension between increasing mass constraints on BSM scalars
and the requirement of additional light scalar degrees of freedom to
accommodate a strong first order EWPT. The findings are of particular interest
for a variety of (non-minimal) split supersymmetry scenarios which necessarily
introduce additional light fermion degrees of freedom.
