In spite of its importance for the study of star formation at all mass domains , the nearby young \sigma Orionis cluster still lacks a comprehensive survey for multiplicity . We try to fill that observational gap by looking for wide resolved binaries with angular separations between 0.4 and 4.0 arcsec . We search for companions to 331 catalogued cluster stellar members and candidates in public K -band UKIDSS images outside the innermost 1 arcmin , which is affected by the glare of the bright , eponymous \sigma Ori multiple system , and investigate their cluster membership with colour-magnitude diagrams and previous knowledge of youth features . Of the 18 identified pairs , ten have very low individual probabilities of chance alignment ( < 1 % ) and are considered here as physical pairs . Four of them are new , while the other six had been discovered previously , but never investigated homogeneously and in detail . Projected physical separations and magnitude differences of the ten probably bound pairs range from 180 to 1220 au , and from 0.0 to 3.4 mag in K , respectively . Besides , we identify two cluster stars with elongated point spread functions . We determine the minimum frequency of wide multiplicity in the interval of projected physical separations s = 160–1600 au in \sigma Orionis at 3.0 ^ { +1.2 } _ { -1.1 } % . We discover a new Lindroos system , find that massive and X-ray stars tend to be in pairs or trios , conclude that multiplicity truncates circumstellar discs and enhances X-ray emission , and ascribe a reported lithium depletion in a young star to unresolved binarity in spectra of moderate resolution . When accounting for all know multiples , including spectroscopic binaries , the minimum frequency of multiplicity increases to about 10 % , which implies that of the order of 80–100 unknown multiple systems still await discovery in \sigma Orionis .