Sh2-261, also known as Sharpless 26 is an emission nebula located in the constellation Orion. It is part of the Sharpless catalog of H II regions and is illuminated by ionized hydrogen gas, primarily excited by the radiation of hot, young stars embedded within it.   The nebula is sometimes called Lower's Nebula after Harold and Charles Lower, amateur astronomers who discovered it in the 1930s.

Sh2-26 is estimated to be around 3,000 – 5,000 light-years from Earth and spans several tens of light-years across.  It contains a sparse but active star-forming region, and it is believes the ionization of the nebula is driven by the hot B-type star LS V +14 18.