BTS' lyrics include social commentary, often incorporating criticism of South Korean society. Songs such as "No More Dream" and "N.O" from their "school trilogy" were motivated by their experiences with South Korea's emphasis on education and called for change to the education system and societal expectations. Their experiences with youth culture in South Korea inspired songs like "Dope" and "Silver Spoon" (Korean: 뱁새; Romanized: Baepsae) from their "youth series," referencing generational disparity and the millennial's giving up of romantic relationships, marriage, children, proper employment, homes, and social life in the face of economic difficulties and societal ills while facing condemnation from the media and older generations. The song "Am I Wrong" from Wings (2016) questioned societal apathy towards the state of current events—the lyric "We're all dogs and pigs / we become dogs because we're angry" referenced the South Korean Ministry of Education official Na Hyang Wook who was a proponent of the caste system and described the average person as "dogs and pigs," and BTS performed the song on television during the 2016 South Korean political scandal that led to the impeachment of ex-President Park Geun Hye. RM and Suga's personal struggles with mental health inspired songs like "Tomorrow", "Intro: The Most Beautiful Moment in Life", "So Far Away", "The Last", and "Forever Rain." "Not Today" from You Never Walk Alone (2017) is an anti-establishment anthem, with messages advocating for minority groups, while "Spring Day" was created to memorialize the victims of the Sewol Ferry tragedy.
BTS' albums have recurring themes that fall under the overarching theme of "reflection of youth." Their "school trilogy" explored "the troubles and anxieties of school-age youth." Their "youth series" "tackled a subject that the vast majority of youth experience, but few pop musicians articulate well: mental health and the desire to belong in society." Wings (2016) focused on temptation and sin. The "Love Yourself" series utilized a narrative form to illustrate the excitement of love, the pains of farewell, and the enlightenment of self-love.
Since their inception, BTS have held the belief that telling their story is the only way for the younger generation to relate to their music. Writing over 90 percent of their lyrics, BTS try to include experiences everyone has felt in life, such as sadness and loneliness, and turn them to something more light and manageable. In regards to their lyricism, RM states he tries to not sound as if they're preaching or reprimanding people in their songs as everyone has different lives and different destinies. When asked if it is difficult to write about things like mental health, Suga responded,
"We feel that people who have the platform to talk about those things really should talk more, because they say depression is something where you go to the hospital and you're diagnosed, but you can't really know until the doctor talks to you. [...] More and more, I think artists or celebrities who have a voice should talk about these problems and bring it up to the surface.
BTS has been praised for "speak[ing] honestly about topics they deem important, even in a conservative society" by Jeff Benjamin in Fuse magazine. South Korean president Moon Jae In, in a letter to BTS, recognized their sincerity and inclusion of diversity as key to their success, writing, "Each of the seven members sings in a way that is true to himself and the life he wants to live. Their melody and lyrics transcend regional borders, language, culture, and institutions."