This work focuses on single-lap adhesive joints made from 2 mm thick Ti6Al4V titanium alloy sheets, bonded with Araldite glue, and subjected to pneumatic ball peening treatment to enhance their shear strength. Studies on the influence of key processing parameters (supply pressure, ball diameter, and processing time) were conducted following the static, deterministic, sequential, polyselective Hartley PS/DS – P:Ha3 plan. These studies resulted in a mathematical model, represented as a second-degree polynomial, which describes the effects of these parameters on both the strength of the joints and the operational costs. Single-criterion optimization was performed for each criterion, revealing the existence of two distinct sets of optimal processing parameters. This finding was the premise for conducting double-criterion optimization, allowing for the identification of a compromise set of pneumatic ball peening parameters. The studies confirmed the effectiveness of pneumatic shot peening, demonstrating the potential to improve shear strength by up to 80%.