  In this paper we initiate the study of correlation functions of a single
trace operator and a circular supersymmetric Wilson loop in ABJM theory. The
single trace operator is in the scalar sector and is an eigenstate of the
planar two-loop dilatation operator. The Wilson loop is in the fundamental
representation of the gauge group or a suitable (super-)group. Such correlation
functions at tree level can be written as an overlap of the Bethe state
corresponding to the single trace operator and a boundary state which
corresponds to the Wilson loop. There are various type of supersymmetric Wilson
loops in ABJM theory. We show that some of them correspond to tree-level
integrable boundary states while some are not. For the tree-level integrable
ones, we prove their integrability and obtain analytic formula for the
overlaps. For the non-integrable ones, we give examples of non-vanishing
overlaps for Bethe states which violate selection rules.
