Bubble traps for use in medical fluid lines and medical fluid bubble trap systems are disclosed herein. In some embodiments, the bubble trap is configured to trap gas (e.g., air) that flows into the bubble trap from a fluid line. In some embodiments, the bubble trap includes an inlet and an outlet and a chamber between the inlet and the outlet. For example, in some embodiments, the bubble trap is configured to inhibit gas from flowing into the outlet once gas flows into the chamber from the inlet. In some embodiments, the bubble trap is in fluid communication with a source container, a destination container, and/or a patient.