No. Let A be the ring k[x,y,z]/(xz,yz) localized at (x,y,z).  Then the dimension of A is 2, but the dimension of A/(x) is one.  Note that xz = 0 in A.

The geometric picture is this: In 3-space, take the union of the horizontal z=0 plane with the vertical line x = y = 0, and look at the local ring at the origin.  Then restricting to x=0, we get the union of the y-axis and the z-axis.