"Goodbye Sengen" (グッバイ宣言, Gubbai Sengen; 'Goodbye Declaration') is a 2020 song written by Japanese music producer Chinozo, utilizing the Vocaloid voice library V Flower. The song is the second-most viewed Vocaloid song on YouTube with more than 100 million views, and received over 3 billion listens on TikTok by 2022.