Den may refer to:

• Lair, a home that wild animals make for themselves
• In the USA, a den can be a family room or a comfort room devoted to reading
• In British children's street culture, a den is a concealed place, unknown to adults, where children can congregate together. Such dens often occur naturally (e.g.: in thickets of bushes or in an abandoned structure); but are then added to with branches, sheeting and improvised seating. A tree house may also serve as a den
• Den (comics), a Richard Corben comic book series
• Den (newspaper), a Ukrainian newspaper
• Den (Pharaoh), a Pharaoh of Egypt
• The Den (television), Irish children's television program
• Denver International Airport (IATA code: DEN)