  We incorporate covers of quasisplit reductive groups into the Langlands
program, defining an L-group associated to such a cover. We work with all
covers that arise from extensions of quasisplit reductive groups by
$\mathbf{K}_2$ -- the class studied by Brylinski and Deligne. We use this
L-group to parameterize genuine irreducible representations in many contexts,
including covers of split tori, unramified representations, and discrete series
for double covers of semisimple groups over $\mathbb R$. An appendix surveys
torsors and gerbes on the \'etale site, as they are used in the construction of
the L-group.
