SJD, or Sean James Donnelly, is a musician from Auckland, New Zealand. His music is a mix of electronica, pop-rock, and soul. The name SJD also refers to Donnelly's touring band when not performing solo.

SJD's debut album 3 was initially self-released on Swarf Records as 120 CD-Rs in 1999 before being picked up by Flavour Distribution. After contributing a track to the Sideways compilation and playing alongside Phase 5 he then signed to the Round Trip Mars label. Second album Lost Soul Music was released in 2001. Southern Lights was released 2004 with assistance from government arts funding agency Creative New Zealand, yielding the single Superman You're Crying which met with some popular success in New Zealand and huge critical acclaim. Sean Donnelly and Angus McNaughton shared the 2005 New Zealand Music Awards Tuis for Best Producer and Best Engineer for their work on Southern Lights. Songs from a Dictaphone was released in July 2007 and followed by Dayglo Spectres, which is a collaborative effort with guitarist and fellow Round Trip Mars artist James Duncan (also in Dimmer), and was released in Oct 2008. His latest album Elastic Wasteland is entirely written, played, produced and mixed by Sean alone and will be released on 16 November 2012.