Loneliness is a complex and usually unpleasant emotional response to isolation or lack of companionship.

Loneliness may also refer to:

• "Loneliness" (short story), a short-story by Charles Bukowski
• Loneliness (album), a 2009 album by Evan Yo
• Loneliness, a 1988 album by Sanchez
• "Loneliness" (song), a song by the German DJ Tomcraft
• "Loneliness", a song by Helen Reddy from Free and Easy
• "Loneliness", a song by Flobots from The Circle in the Square
• "Loneliness", a song by Robert Forster from Warm Nights

• Lonely (disambiguation)
• Lonely Is the Night (disambiguation)
• Lonely Night (disambiguation)
• Lonely Nights (disambiguation)