Insecure attachment has been associated with an array of addictive behaviors. However, the mechanism by which insecure attachment leads to addictive behaviors remains largely unknown. In the present research we tested whether emotion dysregulation mediated the relationship between insecure attachment (anxious, avoidant) in substance use (alcohol, marijuana) and DSM-5 (Internet gaming) and non-DSM-5 (texting) behavioral dependencies. A sample (N = 712) of participants recruited from a university in the United States completed an online battery of instruments, assessing adult attachment style, emotion dysregulation, and self-reported DSM-5 symptoms adapted from substance use disorder criteria. In separate mediation analyses, anxious attachment was associated with self-reported DSM-5 symptoms for alcohol, marijuana, texting, but not Internet gaming; whereas emotion dysregulation was associated with self-reported DSM-5 symptoms of all four potentially addictive behaviors. Avoidant attachment was not associated with self-reported DSM-5 symptoms for any of the addictive behaviors. Emotion dysregulation mediated the relationship between both anxious and avoidant attachment and self-reported DSM-5 symptoms for alcohol, marijuana, and texting. In contrast, emotion dysregulation mediated the relationship between anxious but not avoidant attachment and Internet gaming. Insecure attachment, specifically anxious attachment and emotion dysregulation may be important psychological characteristics that increase the risk for alcohol, marijuana and texting, while Internet gaming corresponds with unique characteristics. Whereas attachment styles may be resistant to change, emotion dysregulation has been found to be modifiable and may provide a potential target in the treatment of substance use disorders and some behavioral dependencies for those who manifest attachment insecurities.