Head coach Roy Williams confirmed that the trio would return to school. The deadline to withdraw was 5 p.m. ET.
Ellington and Green were unable to secure a first-round draft pick guarantee. Their return, coupled with player of the year Tyler Hansbrough's return, makes UNC the prohibitive favorite to win the 2009 national title.
Ellington, Green and Lawson all participated in the Orlando pre-draft camp last month.
Also withdrawing from the draft to return for a senior season was Texas' A.J. Abrams, the guard announced.
Abrams, the all-time leader in 3-pointers made for the Longhorns with 284, helped lead Texas to the Elite Eight, a Big 12 regular-season title and a 31-7 record last season.
"When I sat down with my family and looked at my options, I knew I wanted to come back, finish what I have started," Abrams said in a statement.
Memphis junior Robert Dozier also withdrew from the draft and will return for his final season of eligibility.
"I appreciate the opportunity to go through the process," Dozier said in a statement. "I loved the workouts, and I truly appreciate the honesty of all parties involved, especially the NBA personnel.
"I'm coming back with the mind-set that next year's team can be even better than what we were a year ago, knowing a lot of that will fall on my shoulders," he said.
Memphis made it to the national championship game last season but lost to Kansas 75-68 in overtime.
"I want Robert to come back with two things in mind -- to help the team win a national championship and become the player of the year in college basketball," Memphis head coach John Calipari said in a statement.
Vaden will return for his senior season, Blazers coach Mike Davis told ESPN.com via text message Monday morning. Vaden was projected to be a likely second-round pick had he stayed in the NBA draft.
Pargo will return to the Bulldogs for his senior season after sending in his paperwork to the NBA office Monday afternoon, Gonzaga assistant Tommy Lloyd told ESPN.com. A source close to Steele confirmed his withdrawal to ESPN.com.
Vaden will be a fifth-year senior and will enter the season as one of the top scoring guards in the country. Vaden averaged 21.1 points a game in his only season with the Blazers after transferring from Indiana when Davis left the Hoosiers to coach the Blazers.
With Vaden, UAB should expect to challenge for second place in Conference USA behind likely league favorite Memphis.
Vaden made 142 3-pointers last season.
Pargo, projected as a second-round pick had he stayed in the draft, played in the Orlando pre-draft camp and had a number of workouts in the past 10 days, including working out with Seattle on Sunday. His brother, Jannero Pargo, played for the New Orleans Hornets last season.
Pargo was the WCC Player of the Year last season, averaging 12.1 points and six assists for the Zags. He scored 20 or more points five times during the season.
His return means the Zags will likely be a top-10 preseason team.
Steele sent in the paperwork Monday afternoon in time to beat the deadline to withdraw. Steele worked out Monday morning for Charlotte after working out Sunday for Utah and was at the group workout at the Golden State Warriors' facility earlier in the weekend.
Steele didn't play last season while recovering from knee surgery. He did play at the Orlando pre-draft camp.
Alabama junior forward Richard Hendrix will remain in the draft.
Steele will now play with his brother, Andrew, a point guard who was signed for next season.
Steele's best season was in 2005-06 when he averaged 14.3 points a game for the Tide.
Arizona guard Chase Budinger also decided to return to school. He averaged 17.1 points, 5.4 rebounds and 2.9 assists per game in 34 appearances last season and became the 42nd player in Arizona history to score 1,000 career points on March 6.
Hudson, who averaged 25.7 points last season, became the first Division I men's player to record a quadruple-double -- 25 points, 12 rebounds, 10 assists and 10 steals against Central Baptist.
Information from ESPN.com senior writer Andy Katz and The Associated Press was used in this report.