This disclosure details exemplary traction battery pack venting systems for use in electrified vehicles. An exemplary traction battery pack system may include a venting system having one or more vent ducts for expelling battery vent byproducts from a battery pack. The vent ducts may include a thermal barrier configured to block heat emitted by the battery vent byproducts during cell venting events. In some embodiments, the thermal barrier includes a thermal barrier coating. In other embodiments, the thermal barrier includes both a thermal barrier coating and a thermal barrier layer. In still other embodiments, a second thermal barrier may be applied to vehicle components located near the battery pack for improving the thermal barrier properties.