Augustus’s parents, Cindy and Mark Waters, are warm, family-oriented people. They have a playful relationship with Augustus and endearingly call him by his nickname, Gus. As his health begins to decline, they provide unwavering support as his primary caretakers and find solace in their love for each other.

They welcome Hazel to the family with open arms and immediately invite Hazel to dinner the day that she meets Augustus. Throughout the meal, they do not mention Hazel's oxygen tubes or diagnosis, which Hazel appreciates. When she explains that she refrains from eating meat so that she does not create more death, Cindy simply replies, “Well, I think that's wonderful.” This approach contrasts with Kaitlyn's discomfort whenever death is mentioned in Hazel's presence. Mark and Cindy are extremely perceptive and understand that Hazel and Augustus's illnesses ostracize them from their peers. Consequently, Cindy and Mark want to make them feel as normal as possible. Their treatment of Hazel and Augustus as ordinary teengaers is, in many ways, preferable to Kaitlyn's discomfort or even Lidewij's overt kindness. Cindy and Mark's desire to make Hazel and Augustus feel normal is a recurring theme throughout the novel. On Augustus's “Last Good Day,” Augustus's extended family make a spectacle of him and constantly bring attention to his condition. Hazel swoops in and starts joking with him as if nothing is amiss, and Augustus happily jokes back. In response, Mark pulls Hazel aside and whispers, “I thank God for you every day, kid.” Mark and Cindy both grasp how harmful it is for Augustus to feel more like an other than he already does. They intuitively know that what Augustus needs is not coddling and praise, but the illusion of normalcy.

Their kindness extends beyond Augustus's death. Even in their immense grief, they take the time to assure Hazel that what Augustus felt for her was more than just puppy love. They do not try to keep Augustus to themselves and understand that he was important to Hazel too. When Hazel asks to go through Augustus's things, Mark replies “We’re not ready…[b]ut of course, yes, Hazel. Of course you can.” Their warmth and kindness radiates throughout the novel and remains consistent from beginning to end.