Bernard John "Bernie" Marsden (born 7 May 1951) is an English rock and blues guitarist. He is primarily known for his work with Whitesnake having written or co-written with David Coverdale many of the group's hit songs, such as "Here I Go Again".

Having played with Glenn Cornick's Wild Turkey in 1974, he then played with Babe Ruth, from 1975–76, before becoming an original member of Paice Ashton Lord in 1977 and then joining the hard rock band, Whitesnake, after having the possibility of playing with his boy-time hero Paul McCartney and Wings because while waiting, David Coverdale asked him to form Whitesnake.

In more recent years, Marsden has toured with his bands Company of Snakes and M3 (both formed with fellow former Whitesnake members Micky Moody and Neil Murray) and performed with Elkie Brooks.

Over the years he has taken part in a number of sessions and has released a handful of solo albums (And About Time, Too!, Look at Me Now, Green & Blues, Stacks). He has also collaborated with Micky Moody on a number of Marsden-Moody live and studio projects.

On the Sweden Rock Festival on 10 June 2011 Bernie Marsden played with Whitesnake for the first time since 1981, thus becoming the second of only two former Whitesnake band members who have played with Whitesnake in recent years, the other person being Adrian Vandenberg, who also played with them on the Sweden Rock Festival.

In the last ten years, Marsden has been involved in very different projects. The most unusual being two engagements at the National Theatre in London for Nickolas Hytner's productions of Shakespeare's "The Winter's Tale" and "Henry the V" in collaboration with Simon Webb. Also, he appeared in ZDF television in Germany for their production of "Frankie", a six-part TV special. After this, Marsden has worked alongside Robert Plant, Paul Weller, Ian Paice and Jon Lord for The Sunflower Jam charity concert in London. Bernie also played Guitar with Ringo Starr and his son Zak Starkey in Monte Carlo. Most recently, he has been playing and writing for guitar virtuoso Joe Bonamassa.

Bernie Marsden now endorses PRS Guitars and has his own Signature guitar released in 2012. As of the beginning of 2013, he is recording his new album for Mascot Provogue records at Abbey Road Studios in London and Royal Studios in Memphis. He has also produced a blues documentary, A Day in the Delta, in collaboration with Jim Singleton, filmed in Mississippi for release in late 2013.