Scorpio and Sagittarius are next door neighbors in the Zodiacal neighborhood, which usually don’t get along too famously. These two, like most of the others, are likewise vastly different. For one thing, we’re mixing Fire and Water signs, which usually brings numerous challenges along for the ride. Granted, Scorpio is not the typical Water sign, but they are ruled by emotions and these waters run quite deep. While they’re affectionate, loyal and various other things that make them a good partner, there is an intensity there that is comparable to running on a nuclear reactor as opposed to AA batteries.  As long as everything is in balance everything will be just dandy. Power will be generated, the reactor will heat up but be cooled by lots of water. But if anything goes wrong, particularly overheating, you can have a pretty serious meltdown replete with all the radiation and toxic byproducts. If Fire and Water can achieve a nice, comfortable simmer everything is fine, but once it reaches the boiling point and steam pressure starts to build up, look out.

The Scorpion is also a Fixed sign, meaning they’re set in their ways and those ways are often very closely related to their ruling planet, Pluto. Their native 8^th House rules sex, death and other people’s money. Don’t let the death part scare you unless they’re an ex-felon or something. Pluto transits are usually what are involved with that. Sag, being a Fire sign, can probably deal with the sex part, but there could be problems with the money. And that trouble may be that Sag doesn’t have any, either. Fire signs aren’t exactly known for their frugality (that would be the Earth signs) so it’s likely these two will be perpetually broke, if nothing else, particularly given the 9^th House where Sag calls home. This House covers higher education, long distance travel and legal matters among other things. Sags like to do things in a big way and while they can be extraordinarily lucky given Jupiter as a ruling planet, you still better not count on them winning the lotto anytime soon, though it's always possible.

As for common interests, if Sag is well-respected in his particular domain, say Academia, Scorpio will quite like that because it emanates power, which they like. Scorps are drawn to power like moths to a light bulb. So if Sag is using their intellectual skills and concentrating on one thing enough to make significant progress, there will be something the Scorpion will be very happy with. Sag, on the other hand, can find stability and loyalty in a Scorpio, which Sag may or may not be able to return.

There are a lot of fundamental differences between these two and there is nothing that indicates any exception to the "next door neighbor" being a bad match. Again, compatibilities in Moon signs or Ascendants could soften this, but philosophically these two don’t exactly spell "soul mates" so give it a lot of thought and a long test drive before indulging in some major cathexis.