As there have already mentioned, if the VC wishes to make their participation private, you will likely have a difficult time finding out.
Otherwise, http://crunchbase.com and http://angelist.co are two places you can go to find who has invested in a startup at various levels. You can also do a general Google search for Press Releases about the company, as funding rounds of any substantial amount tend to be announced when they close, with the active participants named in the release.
Originally Posted: https://www.quora.com/Is-there-a-way-to-find-out-which-venture-capital-VC-investors-participated-in-a-startup-funding-round
Originally Posted On: 2015-03-02