A needle safety guard device adapted to attach to a liquid container is provided. The device includes a disk-shaped shield having a medial opening connected with a radial opening between two radial edges. The device also includes a substantially U-shaped holder having two sidewalls coupled substantially perpendicular to the disk-shaped shield along the two radial edges, and a top cover connecting to the two sidewalls and extending from the shield above the radial opening. The U-shaped holder includes a wedged protrusion and a curved protrusion extending from each of the two sidewalls, the curved protrusion being between the top cover and the wedged protrusion for blocking a cap of the liquid container from moving toward the medial opening.