Do you have a picture of the squash plants?

Yes, please post pictures. They can tell us a lot.

Need an image of where they are growing as well as close-ups.

Here's a pic of my little squash plant. I realize now that my garden is too crowded but it doesn't seem like it is too crowded at this point to prohibit it from growing. Thanks for the help!

same plant

Where it is positioned in my garden. The cucumber plants to the right of the squash plant had the same problem for a short while, but have had a turning point and appear to be doing ok.

And these are my two raised beds, taken a few weeks ago. You can see how much better the cucumbers are doing and how the squash hasn't progressed at all.

Do they get a good bit of sun? Do the cucumber pants cast a shadow - too early and/or too long?

Kinda close to the cukes - squash take up quite a bit of real estate - three plants could occupy a decent sized raised bed by themselves.

Got another location that would afford them good sunshine and space?

See how big they can get:

I agree that they are planted to close to the cucumbers. As far as why they're yellowing and not thriving is beyond me because it looks like your cucumbers are doing great.

Oh wow, I way underestimated how big these plants would get! You will laugh when I tell you that I had two other rows of veggies in between the zucchini row behind and the squash/cucumber row! Needless to say, those didn't make it as the zucchini took off and I ripped them out. Well at least we have tons of zucchini, and the cucumber vines are loaded with babies, so no big loss on my yellow squash plant, I suppose. I plan on building more raised beds next year and we will try again.

That looks like some type of inorganic problem. You haven't used any weed killer (glyco, etc) in the area have you? IT can really drift and a very light exposure would causes plants to look this way. Certain other chemicals could do the same, as could salt or certain other things. Any chance you got the dirt from an area that had been exposed to some inorganic substance? Give some thought to these scenarios and any substance that could have affected the plants or soil. Of course, its just one of many possibilities. Good luck.