In this talk, we construct spacelike slant geometry on spacelike submanifolds of codimension two in Lorentz-Minkowski space from the viewpoint of Lagrangian singularity theory. Thus, we generalize some of the results which were obtained by S. Izumiya and M. C. Romero Fuster. Furthermore, we mention about spacelike curves in Lorentz-Minkowski 3-space as an another special case of our results.