You'll want to stay around the warm grays or a "greige" instead of a cooler true gray to stay inline with the olive instead of clash with it. Sherwin-Williams' "Alpaca" and "Functional Gray" worked well in our house.

If you have olive in the adjoining room, I would suggest staying in the gray-green family of undertones. Some suggestions would be Benjamin Moore's OC-23 Classic Gray or HC-172 Revere Pewter.

Agree with Lynne. In order to coordinate the olive and gray walls, a few drops of the same olive will tint the gray enough to coordinate well with the olive if you have chosen the correct new gray to begin with. Test the new gray mix out after you have a sample mixed, on an area that meets the olive, if possible. Look at this combo in daylight as well as in the evening with lights on. Different lighting does a number on painted walls!

Most building centers will mix up a 1/2 pint of a color for you.

You could also bring home paint strips with gray samples on it to see if you hit the right color way. You never know - a nice shade might already be on the shelf.

In any event, the gray should have olive undertones in order to flow - one room to another. Pink or blue undertones will just cause a fight on the walls.

Cut the strips apart into individual rectangles, and lay them away from each other, upside down, on something white. Turn them over, one by one, and you will see the difference in the grays. Pull out the ones that are clearly not "it". You will be able to eliminate most of the rectangles quickly because the unwanted undertones will be obvious. This should be done in different lighting too.

It would also help if you have a sample of your olive paint to lay along side of the gray samples to see the combo. Paint a sample of your olive on white tag board and lay these samples out together but separate the grays away from each other on a white ground.

The white background is really important because of what is called "visual mix". If you look at the olive or gray on, say, a red counter, your eye will also take in the red of the counter and mix that in with the olive and gray, tinting them off their actual hue. White is a neutral color and will not affect the color reading. Too much info? Sorry! Bottom line - always use a white background to find your color.

A consultant at the paint store should be able to help you with this project. I hesitate to recommend a certain color because computer settings are different for everyone and often do not read accurately, one to another.

And I know this sounds like a big hassle, but you will see how it works and save yourself a possible repaint! Trust me on this one!

Yes, I agree with Sandy about looking at paint colours from a white background. It's worth the effort and makes all the difference in how the eye takes in colour.