Can other type of lens be attached to nikon body?

I have a nikon camera. Nikon d5000. I wonder if other lens such as sony, pentax and canon can be attached to it. Nikon lenses are all expensive so I'm trying to buy a little less one.So, can I put it in a nikon body?

You did as I did. Bought the camera with out researching the cost of lenses. In my case it was Pentax. I bit on the fact that older Pentax lenses are supposed to fit their DSLR's. Of the thousands of film based lenses made for pentax I'm having a problem finding any in the "used" section, of B&H Photo, or Adorama. Frankly I'm shy of eBay.
You could check some of the other manufacturers like Tamron and Sigma that come with a Nikon mount. But be warned on this. Don't let the lower price get you something that is not good, for YOU. I purchased a Tamron 18-200mm lens and found it not as sharp(maybe it is trying to be "all things to all people") as I'm use to (being a retired professional).So sold it and bough the Pentax 50-200mm which is the only new Pentax lens I consider reasonable in price. It turned out to be fantastic! But I still have the problem of changing lenses, but that is much better than a neck ache from too big a lens. And it is sharp as a tack. So my advise is don't get carried away with too long, or too big a lens, and you should be fine.

That's a real can or worms without auto functions. See:
http://www.photoimagenews.com/lens.htm
You can also get a T mount adpater that will take certain very old lenses and scope adapters but you will lose auto functions. Waste of time for general use.

Take a look here - it's a Sony Minolta site but they list the Sigmas and Tamron's too.
http://www.dyxum.com/lenses/results.asp?IDLensType=3

Look for ratings above 4.

Generally lenses designed for other cameras do not work well. Although you can buy adapters in some cases, they are in a sense no different than using an extension tube, which converts the lens into a semi-macro lens. That means you will not have infinity focus (ability to focus far objects), and the lens must be used manually; manual exposure, manual focus.

You would be better off buying an older Nikon lens (there are some 70 million to chose from), or an aftermarket lens; Tokina, Sigma, Tamron than trying to adapt a lens intended for another brand camera.

Nikon lens cost more for a reason. Quality! You don't put regular gas in your Maserati.

Sigma, Tamron and Tokina all make lenses to fit Nikon - just make sure they have built-in focus motors (Sigma call theirs, 'HSM,' I'm not sure of the others).

You can use M42 or Pentax screwmount lenses with the use of an M42-to-Nikon lens adapter. If you want to preserve focus to infinity, get an adapter with a corrective optical element. If you want to preserve the optical quality of the lens (especially if you're using Zeiss or Takumar lenses), get an adapter that does not have an optical element (the cheaper one). Bear in mind that you will lose all automatic functions including the lightmeter so you will be left on your own. If you get it right though, everything will be worth it and may even convince you to jumpship to a better brand that uses these old lenses. Wink, wink!

It depends - have a look and work out what mount your camera has and then see whether the new lens you want to buy fits in with that mount? If you get what i'm saying. So yes probably it will fit if you nikon has fairly standard mount dimensions.