  We study left-invariant generalized K\"ahler structures on almost abelian Lie
groups, i.e., on solvable Lie groups with a codimension-one abelian normal
subgroup. In particular, we classify six-dimensional almost abelian Lie groups
which admit a left-invariant complex structure and establish which of those
have a left-invariant Hermitian structure whose fundamental 2-form is $\partial
\bar \partial$-closed. We obtain a classification of six-dimensional
generalized K\"ahler almost abelian Lie groups and determine the 6-dimensional
compact almost abelian solvmanifolds admitting an invariant generalized
K\"ahler structure. Moreover, we prove some results in relation to the
existence of holomorphic Poisson structures and to the pluriclosed flow.
