Negative space (also called void or counter-form) in architecture and design refers to the unoccupied space around, between, and within built forms.

It is as important as positive (built) space in defining the quality of architecture:

• The courtyard of a building is negative space that organises surrounding rooms.
• The gap between two buildings creates a negative space that functions as a street or plaza.
• Frank Lloyd Wright's concept: 'The reality of a building is the space within.'

Understanding negative space is fundamental to spatial composition in architecture and urban design.