The main aim of this chapter is to study the geometrical properties of almost Yamabe solitons and gradient almost Yamabe solitons on generalized Sasakian space forms with the \(\beta \) -Kenmotsu structure \(M(f_1, f_2, f_3)\) . It is proven that if \(M(f_1, f_2, f_3)\) admits an almost Yamabe soliton \((g, \xi , \lambda )\) , then \(M(f_1, f_2, f_3)\) is cosymplectic and the Reeb vector field of \(M(f_1, f_2, f_3)\) is Killing. Consequently, we establish the conditions under which the almost Yamabe soliton on \(M(f_1, f_2, f_3)\) is expanding, shrinking, and steady. We also prove that if \(M(f_1, f_2, f_3)\) admits an almost Yamabe soliton \((g, V, \lambda )\) , where \(V=h\xi \) , then h satisfies the time-independent Klein–Gordon equation or the homogeneous screened Poisson equation (25). The geometrical properties of \(M(f_1, f_2, f_3)\) that admit a gradient almost Yamabe soliton are explored, and it is proven that the manifold is a Sasakian manifold.