The reactions of difluoro-, dichloro- and dibromocarbene with quadricyclane (2) were examined. In all cases, conversions were low (4–15%), but three distinct reaction courses were observed: cleavage, 1,2-addition, and 1,4-addition. Difluorocarbene gave mainly 6-endo-(2,2-difluorovinyl)-cis-bicyclo[3.1.0]hex-2-ene (8; 52–89% relative yield), together with minor amounts of exo-3,3-difluorotricyclo[3.2.1.0^2,4]oct-6-ene (7; 13–17%), and 4,4-difluorotetracyclo[3.3.0.0^2,8.0^3,6]octane (5; 2–4%). Dichlorocarbene gave analogous products, but in relative yields of 35 (17), 51 (11), and 12% (16). The product 11 of 1,2-endo addition underwent further rearrangement to its allylic derivative 12. A small amount of 1,2-endo addition also occurred (2% of 14/15). Dibromocarbene gave predominantly products derived from rearrangement of the 1,2-exo (61% of 20/21) and 1,2-endo adducts (10% of 23/24). In addition, a significant amount of 4,4-dibromotetracyclo[3.3.0.0^2,8.0^3,6]octane (25; 21%) was formed. The cleavage product, 6-endo-(2,2-dibromovinyl)-cis-bicyclo[3.1.0]hex-2-ene (26) was also observed (7%). The yields and product compositions were compared to those obtained from norbornadiene (1) and found to be entirely different (Table 1), for example no cleavage occurred with difluorocarbene.