[en] The title compound was prepared from the elements by arc-melting. The crystal structure was investigated by means of single-crystal X-ray diffraction. It crystallizes in the TbFeSi${}_2$ structure type, orthorhombic space group Cmmm, a = 4.0496(8), b = 16.416(2), c = 3.9527(6) Å, Z = 4, R1 = 0.041, wR2 = 0.11 for 207 unique reflections with I${}_o$ > 2 σ(I${}_o$) and 19 refined parameters. The Fe position is not fully occupied and the refinement results in a composition GdFe${}_{0.68}$Si${}_2$ in agreement with a chemical analysis. The structure consists of zig-zag chains of Si(1) atoms which are terminally bound to additional Si(2) atoms. For an ordered variant GdFe${}_{0.5}$Si${}_2$ the Zintl concept can be applied which results in formal oxidation states Gd${}^{3+}$(Fe${}^{2+}$)${}_{0.5}$Si(1)${}^{1-<!--\; ???\; -->}$Si(2)${}^{3-<!--\; ???\; -->}$. The electronic structure of this variant GdFe${}_{0.5}$Si${}_2$ was analyzed using the tightbinding LMTO method and the results confirm the simple bonding picture.