Harry Potter and the Order of the Phoenix Movie Cast List

Daniel Radcliffe Harry Potter
Emma Watson Hermione Granger
Rupert Grint Ron Weasley
Ralph Fiennes Lord Voldemort
Gary Oldman Sirius Black
Helena Bonham Carter Bellatrix Lestrange
Imelda Staunton Dolores Umbridge
Evanna Lynch Luna Lovegood
George Harris Kingsley Shacklebolt
Natalia Tena Nymphadora Tonks
Kathryn Hunter Mrs. Arabella Figg
Maggie Smith Minerva McGonagall
Robbie Coltrane Rubeus Hagrid
Alan Rickman Severus Snape
Jason Isaacs Lucius Malfoy
Katie Leung Cho Chang
Matthew Lewis Neville Longbottom
James Phelps Fred Weasley
Oliver Phelps George Wesley
Bonnie Wright Ginny Weasley
Warwick Davis Filius Flitwick
Tom Felton Draco Malfoy
Jamie Waylett Vincent Crabbe
Harry Melling Dudley Dursley
Jason Boyd Piers
Richard Macklin Malcolm
Miles Jupp TV Weatherman
Fiona Shaw Petunia Dursley
Richard Griffiths Vernon Dursley
Jessica Stevenson Mafalda Hopkirk
Adrian Rawlins James Potter
Geraldine Somerville Lily Potter
Robert Pattinson Cedric Diggory
Brendan Gleeson Alastor 'Mad-Eye' Moody
Peter Cartwright Elphias Doge
Bridgette Millar Emmeline Vance
Mark Williams Arthur Weasley
David Thewlis Remus Lupin
Julie Walters Mrs. Weasley
Timothy Bateson (II) Kreacher
Jamie Wolpert Newspaper Vendor
Nicholas Blane Bob
Robert Hardy Cornelius Fudge
Chris Rankin Percy Weasley
Michael Gambon Albus Dumbledore
Sian Thomas (II) Amelia Bones
Joshua Herdman Gregory Goyle
David Bradley Argus Filch
Devon Murray Seamus Finnigan
William Melling Nigel 2nd Year
Apple Brook Professor Grubbly-Plank
Emma Thompson Sybil Trelawney
Alfie Enoch Dean Thomas
Afshan Azad Padma Patil
Shefali Chowdhury Parvati Patil
Jim McManus Barman
Nick Shrim Somewhat Doubtful Boy
Sam Beazley Everard
John Atterbury Phineas
Arben Bajraktaraj Azkaban Death Eater
Richard Leaf Dawlish
Tony Maudsley Grawp
Alec Hopkins Young Severus Snape
Robert Jarvis Young James Potter
James Utechin Young Remus Lupin
Jason Piper Centaur
Michael Wildman Centaur
Richard Cubison Death Eater
Richard Trinder Death Eater
Tav MacDougall Death Eater
Alfred Enoch Dean Thomas
Ryan Nelson Slightly Creepy Boy
Nick Shim Somewhat Doubtful Boy
Daisy Haggard

Wikipedia has the complete cast list with corresponding characters they play in The Order of the Pheonix movie.

FYI, at 2 hours & 18 minutes, this movie is LONG. Either you'll love it and are grateful that there's so much of it to watch, or you'll be sitting there thinking of all the places they could have cut the movie shorter.