OH MY GIRL

The music video for their lead track "Closer" was released on October 7. On December 11, the group flew to LA for a photoshoot for their next album jacket and to perform at a special event, but could not get cleared by customs to enter the US. The group's management claimed that customs mistook the girls for underage prostitutes due to props and outfits for their special performance at an event on the Saturday of that week, and that they were detained for 15 hours.

However, an official with the U. S. Customs and Border Protection later stated that management was lying about the reason for being denied entry.

Upon seeing the contents of the performers' luggage, customs officials determined the group was entering the U. S. to perform, not to go sightseeing as the group had claimed.

As the group did not have the required P1 performance visa, they were denied entry. The customs official denied that the group was "detained" for 15 hours, noting that they were put on the first available flight back to Korea on the airline they traveled with. On March 24, 2016, a comeback teaser was released on 1thek's and the group's official YouTube channel.

OH MY GIRL released their third mini-album, Pink Ocean, on March 28. The group promoted both the title track "Liar Liar" and "Step by Step", a B-side written by B1A4's Jinyoung, on their comeback stages and at guerrilla concerts in Hongdae and Sinchon. On March 28, the group announced their official fandom name "Miracle" at their comeback showcase for "Pink Ocean" and also on the group's V-app on the same day.

On May 26, the group released a repackage mini album titled Windy Day lead by a title track of the same name. On August 1, OH MY GIRL released their first summer special album Listen To My Word which consisted of remakes from various artists. The group promoted the title track "Listen To My Word( A-ing)".

On March 22, 2017, the group teased their 4th mini album on their social media accounts. Coloring Book was released on April 3. On October 30, JinE announced her departure from the group on their fancafe due to ongoing health issues and her contract with WM Entertainment has been terminated.

On December 27, a teaser was posted on the group's official channel on V Live for their upcoming release scheduled for release in January 2018. On January 9, 2018, OH MY GIRL released their fifth mini-album Secret Garden. On April 2, OH MY GIRL BANHANA released a special unit album titled Banana Allergy Monkey.

The group was split into two units for the songs with "Banana Allergy Monkeys" being Hyojung, Yubin, and Arin. Meanwhile, members Mimi, YooA, Seunghee, and Jiho were featured on the album as "Banana Monkeys Without Allergies". On August 29, OH MY GIRL BANHANA, the first sub-unit of OH MY GIRL, made their Japanese debut with the mini album Banana ga Taberenai Saru.

The mini album included Japanese versions of the songs from Banana Allergy Monkey and more. On September 10, the group released their sixth mini album Remember Me. On December 10, they participated in the yearly collaboration single, "Hello!

WM", with other WM Entertainment artists, B1A4 and ONF. The Japanese version of "Remember Me" was pre-released on digital platforms on December 21 while Japanese version of "Secret Garden" was pre-released on December 28, 2018. The two songs were later included in OH MY GIRL's debut Japanese studio album.

On January 9, 2019, they made their Japanese debut with the Japanese ...