A study is reported of the single direction shear transfer strength of lightweight aggregate concrete. Push-off tests were carried out on specimens made from sanded lightweight concrete, two types of all lightweight concrete, and sand and gravel concrete. Both initially uncracked specimens and specimens cracked in the shear plane before being subjected to shear, were tested. It was found that the shear transfer strength of lightweight concrete is less than that of sand and gravel concrete having the same compressive strength. The shear-friction provisions of Section 11.15 of ACI 318-71 may be used in the design of connections in lightweight concrete providing the value of the coefficients of friction, contained in Section 11.15.4, are multipled by the following factors (a) For all-lightweight concrete having a unit weight not less than 92 lb per cu ft (1488.43 kg per cu m), multiply the coefficient of friction by 0.75; and (b) For sanded lightweight concrete having a unit weight not less than 105 lb per cu ft (1698.75 kp per cu m), multiply the coefficient of friction by 0.85. /Author/