Stella is theatrical royalty who instills in her students a sense of the nobility of acting. She dares her students to act, to lift their bodies and their voices, to be larger than themselves, to love language and ideas.
Foster Hirsch, "A Method to Their Madness" (1984), quoted in 
Stella Adler was much more than a teacher of acting. Through her work she imparts the most valuable kind of information - how to discover the nature of our own emotional mechanics and therefore those of others. She never lent herself to vulgar exploitations, as some other well-known so-called "methods" of acting have done. As a result, her contributions to the theatrical culture have remained largely unknown, unrecognized, and unappreciated.
Marlon Brando, preface to Stella Adler: The Art of Acting (2000), ed. Howard Kissel, p. 7
What an extraordinary combination was Stella Adler - a goddess of full of magic and mystery, a child full of innocence and vulnerability.
Elaine Stritch, attributed without citation in Robert Barton, Acting: Onstage and Off (2009), p. 158
[Adler] established the value of the actor putting himself in the place of the character rather than vice versa … More than anyone else, Stella Adler brought into public awareness all the close careful attention to text and analysis Stanislavski endorsed.