A retaining wall structure built of wall-building units such as sand/soil bags or hardenable building units such as clay bricks has interconnecting members placed between adjacent courses of units to attach the adjacent courses to one another. The interconnecting members are plates having projections on both sides which protrude into the wall-building units of the adjacent courses. Sheets of geogrid preferably extend from between some of the courses of wall-building units into the fill retained by the wall-building units. Projections on the interconnecting members protrude through holes in the geogrid sheet, anchoring the wall face to the reinforced soil structure.