Objective: Attachment security and autonomy were examined in adults with ADHD. Insecure attachment and autonomy problems were expected to be negatively associated with general psychological functioning. Method: Questionnaires were administered (Relationship Questionnaire, Autonomy-Connectedness Scale, Brief Symptom Inventory) in 84 late-diagnosed adults with ADHD. Results: Only 18% of participants were securely attached, as opposed to 59% in the normal population. Concerning autonomy, participants scored below average on self-awareness, above average on sensitivity to others, and average on capacity to manage new situations compared with the normal population. The preoccupiedly attached group reported more problems in psychological functioning than the secure and dismissive group. Sensitivity to others and capacity to manage new situations were associated with psychological functioning; self-awareness was not. Attachment security and autonomy contributed to general psychological functioning. Conclusion: Attachment and autonomy problems do exist in adults with ADHD and contribute negatively to their psychological functioning.