The prefix "JR" had to be added to "Kyoto Line" in this unofficial name to prevent confusion as this line connects with the Hankyu Kyoto Line, operated by the Hankyu Corporation (nearly all of which runs in parallel with the JR Kyoto Line), at Osaka (Umeda) Station and the Kintetsu Kyoto Line, operated by the Kintetsu Corporation, at Kyoto Station.
ほぼ全区間阪急電鉄の阪急京都本線（京都線）と並行し、近畿日本鉄道にも近鉄京都線があって、それぞれ大阪（梅田）駅、京都駅で接続しているため、混同を避けるために愛称に「JR」と付けている。