<jats:title>Abstract</jats:title><jats:p>In addition to the ω‐5 olefinic acids found in other<jats:italic>Grevillea</jats:italic> species, about 10% of the acyl groups of<jats:italic>G. decora</jats:italic> seed oil contain a hydroxy group and an ω‐5 double bond. The chainlengths of these acids are from C<jats:sub>22</jats:sub> to C<jats:sub>30</jats:sub>, with the largest concentration at the C<jats:sub>26</jats:sub> and C<jats:sub>28</jats:sub> chainlengths. The hydroxy group is located on odd carbons from carbon‐5 through carbon‐13. These acids previously were unknown in nature. The most abundant of these are 7‐hydroxy‐<jats:italic>cis</jats:italic>‐17‐docosenoic, 7‐hydroxy‐<jats:italic>cis</jats:italic>‐19‐tetracosenoic, 9‐hydroxy‐<jats:italic>cis</jats:italic>‐19‐tetracosenoic, 9‐hydroxy‐<jats:italic>cis</jats:italic>‐21‐hexacosenoic, 11‐hydroxy‐<jats:italic>cis</jats:italic>‐21‐hexacosenoic, and 13‐hydroxy‐<jats:italic>cis</jats:italic>‐23‐octacosenoic acids. The oil also contains the largest known concentration of the unoxygenated C<jats:sub>26</jats:sub> and C<jats:sub>28</jats:sub> ω‐5 monoenes.