Kitchen lights are tied to two sets of switches. If I turn them on with one, I can't turn them off with the other. Any suggestions?

One of the switches is probably wired incorrectly. 3 way have to be connected in a particular way. Did you install the switches?

If you have 2 switches and they are at different locations, they should have 3 wires going to the switch. A red,a black and a white plus a ground(bare) wire.
Check the wiring and let us know what you have at each location and we can help you.

Chuck