- Name: Okada Yui (岡田唯)
- Nickname: Okappai, Okayan, Yuiyan
- Birthday: December 28, 1987
- Birthplace: Osaka, Osaka Prefecture, Japan
- Blood Type: A
- Height: 158cm
- Hobbies: Shopping, manicures, listening to music, and watching movies
- Charm Point: Eyes
- Hello! Project Groups:
- Shuffle Groups:
- 2004: H.P. All Stars
Okada Yui was one of the 2004 Hello! Pro Egg Audition winners. She was most well-known as a memberof the group v-u-den, along with Ishikawa Rika and Miyoshi Erika. Beyond v-u-den, Okada participated in several Hello! Project activities; She was added to the Hello! Project kickbase team Metro Rabbits H.P. in 2006 and was cast, along with her fellow v-u-den members and Matsuura Aya, in the movie Sukeban Deka Codename = Asamiya Saki.
It was announced in January of 2008 that v-u-den would cease activity at the end of their 2008 summer tour. Yui remained in Hello! Project until the entire Elder Club graduated from Hello! Project. Since then, she has performed on occasion with SINA in their mini concerts, and has appeared in a number of concerts/events in the Kansai area.
In December of 2009, Yui and Erika briefly reunited to perform two live shows: the MIYO-YUI no Kyounen mo Futaribocchi Casual Dinner Show on December 20th and the MIYO-YUI no Kyounen mo Futaribocchi Special Live on December 23rd. Many v-u-den songs were featured, as well as some cover songs. On June 23, 2010, she announced her intent to retire from celebrity life to focus on studying beauty and cosmetics. In July of 2011 Yui became a Circuit Lady (racing queen) for Dandelion Racing.
In 2013, Okada would launch the fashion brand "IVORA", as well as model for many of the articles of clothing on sale. Friend and former band-mate Miyoshi Erika endorsed the brand.
- [2005.03.05] ハロハロ！ 三好絵梨香＆岡田唯 写真集from美勇伝 (Hello!x2 Miyoshi Erika & Okada Yui from v-u-den) (with Miyoshi Erika) amazon.co.jp
- [2006.02.21] I DOLL―岡田唯ファーストソロ (I DOLL - Okada Yui First Solo) amazon.co.jp
- [2007.01.28] Yui Okada Hello! Project 2007 Winter Concert
- [2006.03.01] I DOLL ~岡田唯ファーストソロDVDin沖縄~ amazon.co.jp
-  スケバン刑事 コードネーム=麻宮サキ (Sukeban Deka Codename Asamiya Saki)
- She is left handed.
- She is good friends with Miyoshi Erika and often appears on her blog.
- She is friends with Kago Ai. The two followed each other on Twitter in 2013, and it was implied that they met up as well.
- She's translated C-ute's Bye Bye Bye! lyrics to Kansai dialect, they got read in a radio show by Umeda Erika and Yajima Maimi.