The character known as the Engineer's wife is an unnamed human female who appears in the film Transformers: Dark of the Moon. Her name is identified as Julia Singer in the novel adaptation of the film. She is the wife of Bob Singer, an engineer employed by NASA, and the mother of their young daughter, Madeline. The family resides in a suburban home.

Very little of her personality is directly depicted due to her brief screen time. Her primary action in the story is a reaction of shock and fear, leading her to shout at a hostile entity she discovers in her home in an attempt to protect her family. Her core motivation appears to be the protection of her daughter from an immediate and terrifying threat. Her role in the story is that of a victim and a witness. She inadvertently discovers the presence of a Decepticon, a small robotic creature resembling a pink robot, which her daughter has been interacting with while reading. When this creature transforms into a more menacing form, she instinctively confronts it, but is powerless to prevent the subsequent violence. Her function in the narrative is to demonstrate the reach of the Decepticons' conspiracy, showing that they will eliminate even seemingly insignificant individuals like a civil servant's family to protect their secrets. Her key relationships are with her husband, Bob Singer, and her daughter, Madeline. It is implied that her husband had been unknowingly involved in a conspiracy to cover up a spacecraft crash on the Moon, a secret the Decepticons are desperate to maintain. The Engineer's wife has no discernible character development, as she is a minor figure who appears only in a single sequence. She has no notable abilities or skills that are relevant to the plot, beyond a normal human's capacity for fear and a maternal instinct to protect her child. Her primary narrative purpose is to be a victim, highlighting the merciless nature of the Decepticons and the far-reaching stakes of the film's conflict.