This paper presents observations from the physical model tests of retaining walls with different sand–tire chips mixing ratios subjected to horizontal base excitation (Four Earthquake motions applied). A computer-controlled hydraulically driven single-degree-of-freedom shake table is used in these tests. The retaining wall model of 600 mm height was constructed in a Perspex container of 1200 mm × 600 mm in plan and 1000 mm in height. STC mixtures with different tire chips proportions, such as 10, 20, 30, 40, 50%, and Pure sand (Control Case) are considered as backfill materials. Model wall behavior in terms of displacement, earth pressures, and accelerations was being discussed for sand and STC mixtures. Based on experimental results, use of scrap tire-derived materials mixed with sand can provide an alternative backfill material for seismic protection of retaining walls and reduce the huge stockpile of scrap tires from all over the world.