AbstractThe present paper investigates the weak convergence behavior of iterative sequences generated by the Mann-type iteration process for quasi-nonexpansive mappings in real Banach spaces. Starting from the classical framework introduced by Mann, we extend the analysis to quasinonexpansive operators defined on closed convex subsets of Banach spaces. By employing fundamental geometric properties of Banach spaces, together with the demiclosedness principle, we establish that the operator (I −T) associated with a quasi-nonexpansive mapping T is demiclosed at zero. This property plays a crucial role in proving the weak convergence of the Mann iterative scheme. Under appropriate control conditions on the sequence{xn}, it is shown that the sequence {ρn} generated by ρn+1 = xnρn + (1 − xn)Tρn converges weakly to a fixed point of T. The obtained results generalize and improve several existing weak convergence theorems for nonexpansive and quasi-nonexpansive mappings, and provide a unified analytical approach for studying iterative algorithms in Banach spaces.