Lie centre-by-metabelian group algebras over fields have been classified by various authors. This classification is extended to group algebras over commutative rings. 2002 Elsevier Science (USA) Let G be a group (not necessarily finite), and let kG be its group algebra over some commutative ring k (with unit). For subsets X Y of kG, we denote by X Y the k-span of all elements x y = xy − yx with x ∈ X, y ∈ Y . The first and second derived Lie ideals of kG are defined as kG = kG kG and kG = kG kG , respectively. We call kG Lie centre-by-metabelian, if kG kG = 0.If char k = 0, then, by a general theorem of Passi et al. [4], kG Lie centre-by-metabelian implies that G is abelian (see also [9, Theorem V.4.6]). The classification for the case where k is a field of characteristic p > 0 is distributed among several articles by Külshammer, Sahai, Sharma, Srivastava, and myself [3,[5][6][7][8]10]. The results found there carry over to the case where k is a ring of prime characteristic p, since p ⊆ k, and is bilinear. Hence we may state Theorem 1 ([3, 5-8, 10] (i) p = 3, and G = 3.