A female terminal fitting (20) has an approximately tubular connection portion (22) with an open front end for receiving a tab (14) of a male terminal fitting (10). Concavities (30) extend longitudinally in the connection portion (22) at positions opposed to side surfaces of the tab (14). The concavities (30) enable the outside width (W) of the connection portion (22) to be small while securing a large clearance (C) outward from the side surfaces of the tab (14). The concavities (30) do not significantly decrease the strength of the entire connection portion (22). Additionally, the large clearance (C) avoids the need for highly accurate manufacturing.
