On the Billboard 200 chart, Kill This Love debuted at number twenty four with 19,200 units, including over 9,100 pure sales moved. The EP reached the top ten in many territories, including Canada, Japan, New Zealand and South Korea, and the top twenty in Australia. It was certified Platinum by the Gaon Music Chart in June 2019 for selling 250,000 units, becoming Blackpink's second EP to do so after 2018's Square Up, and was later certified 2x Platinum in September 2021 for selling 500,000 units.
Yang Hyun-suk, founder of YG announced on February 8, 2019 that Blackpink was set for a new release with an EP in March. The single and EP were announced on March 25. Between March 31 and April 1, multiple individual teaser pictures were posted onto their social media accounts. On July 26, it was announced that the group would release a Japanese version of their EP Kill This Love on September 11, 2019. The album missed its initial release date and was released on October 16, 2019. No song of the version was released as a single. A live recording of the Japanese version of "Kill This Love", recorded in the Tokyo Dome on December 4, 2019, was included in the group's third live album Blackpink 2019-2020 World Tour In Your Area – Tokyo Dome, released on May 6, 2020, through Universal Music Japan.
The opening track, "Kill This Love" is a stomping, brassy electropop track with trap elements. The song contains "blaring horns and martial percussion", with Rosé and Jisoo leading the "impassioned" pre-choruses about breaking up. The second track, "Don't Know What To Do" is an EDM and pop song with throbbing bass, whistle-like hook and an acoustic guitar. "Kick It", the third song, is a song with elements of Southern trap, synth bass and acoustic guitar. The song is about telling past lovers: “I’m okay being alone / Don’t feel bad for me / I’m going to forget you now. The fourth track, "Hope Not", is a soft, acousticpop-rockballadry about break-up where the person has moved on from yearning to acceptance. The closing track, "Ddu-Du Ddu-Du (remix)" was described as a "quivering, womping club-ready Remix".
Kill This Love was met with generally favorable reviews from critics. At Metacritic, which assigns a normalized rating out of 100 to reviews from mainstream publications, the album received a weighted average score of 69 based on 4 reviews, indicating "generally favorable reviews". Laura Dzubay of Consequence of Sound said that the album "functions as a crisper, tighter, and even more badass lunge into the same ideas as last year’s album". She also noted the "balanced production styles, combined with the singers’ talents for vocal elasticity."
For Rolling Stone, Jeff Benjamin wrote that "There will be time for Blackpink to experiment—ideally in a full-length project. Until then, the women are deepening their brand of K-pop for a quickly growing, language-agnostic fanbase eagerly anticipating every fierce new beat drop." Michelle Kim from Pitchfork gave a mixed review, calling the album's production "weirdly dated, like it was crafted earlier in the decade and then forgotten in a time capsule for five years." Rhian Daly of NME said that the album "showcases a band who are certainly talented but perhaps not quite ready for the next upward arc in the ride they’re currently on."
"Kill This Love" was released on April 4, 2019, as the lead single from the extended play. An accompanying music video for the song was directed by Seo Hyun-seung and uploaded onto Blackpink's YouTube channel simultaneously with the single's release. Upon release, the music video broke the record for the most views within 24 hours, accumulating 56.7 million views. Furthermore, it became the fastest video to reach 100 million views on YouTube, doing so in approximately 2 days and 14 hours, beating the record set by fellow Korean artist Psy with "Gentleman" in 2013. Commercially, the single reached the charts in 27 countries. It peaked at number two in South Korea and became the group's first top-50 hit in the United States and the United Kingdom, thus also becoming the highest-charting female K-pop song on the Billboard Hot 100 at the time.