I have been getting grass clippings from my neighbors for my compost pile. It has just been the last couple of months that I have done this. My compost seems to be doing great, with earth worms and rich soil. What I am wondering is, I am not sure what chemicals if any have been put on the neighbors lawns. Does this mean that my compost could possibly no longer be organic? I just thought of this after I put somemore of the clippings on today. It has never even been an issue to me because I felt like I was receiving the best gift I could get!!

Most everything breaks down in hot compost. There are two exceptions I know of, picloram and chlopiralid (sp on both).
Look these up and find out what if any common lawn products contain them. Then ask your neighbors if they use these products. Maybe someone knows the answer to my question and will save you the research.
If it were me I would continue what your are doing. I don't have your situation because we have livestock that generates spent hay, bedding and manure. I do pick up leaves on the side of the road, they are 99.9% safe.
Tony M

Tip: Get a compost thermometer to make sure the compost gets hot enough. See http://compost.css.cornell.edu/monitor/monitortemp.html