A retaining wall system formed from a wire facing unit having an upstanding face section and a rearwardly extending floor section the rear end of which is provided with aligned, transversely extending, openings defined by upstanding, inserted U-shaped, in the wire elements. The apertures in the forward portion of a geogrid, preferably an integral, uniaxially-stretched, polymer geogrid, can be seated over the protuberances and a connecting rod inserted through the openings to secure the geogrid to the wire facing unit. Strengthening struts can be engaged between cross-wires at the top of the face section of the wire facing unit and at the rear of the floor section of the wire facing unit. An aggregate, including soil or the like, can then be placed behind the face section and over the floor section of the wire facing unit and over the geogrid to form a geogrid-reinforced retaining wall section. Multiple sections may be formed side-by-side and multiple tiers can be constructed with the front faces of superior sections aligned or set back from each other to permit plantings to be placed in front of superior face sections. The connecting rod may be rigid. Alternatively, the connecting rod may be resilient or flexible to facilitate inserting the same between a pair of wires into the aligned openings formed by the protuberances, particularly for interior wire facing units in a series of laterally juxtaposed sections where access to the openings from the sides of the wire facing unit is difficult.