A high density backplane connector (100) includes a group of terminal pairs (17, 18, 27, 28) arranged along a first direction. Each terminal pair includes a first terminals (12, 22) and a second terminals (14, 24) substantially aligned with each other along a second direction perpendicular to the first direction. The first terminal has a first engaging portion (124, 224) and a first tail portion (125, 225). The second terminal has a second engaging portion (144, 244) extending beyond the first engaging portion and a second tail portion (145, 245). The first and second tail portions of the terminal pairs are arranged substantially in a line.