Tiled-monitor large displays are widely used in various application domains. However, how their interior bezels affect user performance and behavior has not been fully understood. We conducted three controlled experiments to investigate effects of tiled-monitor interior bezels on visual search, straight-tunnel steering, and target selection tasks. The conclusions of our paper are: 1) interior bezels do not affect visual search time nor error rate; however, splitting objects across bezels is detrimental to search accuracy, 2) interior bezels are detrimental to straight-tunnel steering, but not to target selection. In addition, we discuss how interior bezels affect user behaviors, and suggest guidelines for effectively using tiled-monitor large displays and designing user interfaces suited to them. Author Keywords Tiled-monitor large display, interior bezels, visual search, tunnel steering, target selection. ACM Classification Keywords H5.m. Information interfaces and presentation (e.g....