Are the roaches I am seeing possibly coming from my neighbor's house? This is a question you hear often, and the answer is yes, it is possible. Roach problems like this between neighbors often happen more in row home or apartment and condo situations. With the close proximity of a row home and sometimes with the common joist set up, or in the case of apartments where pipes and wires are all common, it is the perfect highway set up for roaches to travel back and forth.
If you are faced with this problem it is best to team up with your neighbor, swallow your pride, and set up pest control services for all the homes affected.
Once thing you don't want to do is set off "bug foggers" in your home. This will only spread roaches back and forth for sure.