- Alternate Character Interpretation: Due to not wanting to hinder Montgomery Clift's status as a romantic leading man, the movie made some changes to Morris's personality, intentionally allowing for this trope. The answer to the question of his true intentions with Catherine changes from he definitely only wanted her money to he probably only wanted her money.
- Fair for Its Day: While the ending could definitely be interpreted as Catherine giving up on love and never marrying due to her experiences with her father and Morris, she seems to have not been interested in romance in general—when Morris comes to try to persuade her to marry him again, he assumes that she never married because she was waiting for him. Over the years, Catherine had turned down many perfectly serviceable men and she tells him point blank that she never married because she didn't need to. Most importantly, her eventual spinsterhood is not played for tragedy, just a fact of life. This is something rarely seen even in modern works.
- Hollywood Homely /Informed Deformity: Olivia de Havilland as the plain Catherine.
- Misaimed Fandom: After the release of The Heiress, Olivia de Havilland actually received hate mail from fangirls of Montgomery Clift who completely missed the point of the story.
- Woobie: Many of Catherine's lines towards the end of The Heiress really exemplify how cruelly she had been treated in her life:
Aunt Penniman: Can you be so cruel?Catherine: Yes, I can be very cruel. I have been taught by masters.