A fiber optic seal assembly tool has a stripper for stripping a predetermined length of tubing from an end of a fiber optic bundle. The stripped end is inserted in a seal block and the block is gripped in a hand tool. An actuating lever is squeezed, biasing bundle clamps closed, and sliding a grooved anvil toward the block to press a collet chuck which holds the fiber ends into the block. When the collet is pressed into the block, ends of the fibers are sheared by a knife which moves in the anvil opening.