Background and Objectives Many studies investigated the association between attention-deficit/hyperactivity disorder (ADHD) and substance use disorders (SUDs) but none focused on the association between ADHD and nonmedical prescription opioids such as tramadol. The objective of this study was to assess the prevalence, correlates, and consequences of co-occurrence of ADHD and tramadol use among adults. Methods This study included 122 Egyptian adults with opioid use disorders attributed to tramadol (N = 122). Participants were recruited from the psychiatric outpatient clinic and inpatient unit of Zagazig University Hospital, Egypt. ADHD and SUDs were assessed by using the Adult ADHD Self-Report Scale (ASRS—v 1.1) and SCID-I criteria of DSM-5, respectively. All participants were screened for drugs by urinalysis. Results Forty percent of the participants used tramadol alone, whereas the remaining used it with other substances, such as alcohol (51.6%) and cannabis (48.4%). Thirty-eight cases (31%) had adult ADHD and most of them had inattentive or mixed types. Adults with tramadol use and ADHD were more likely to have a younger age of onset of tramadol use, use a higher dose of tramadol, and use it for a longer duration than those with tramadol use without ADHD. Conclusions and Discussion ADHD in adults with tramadol use is common and is associated with early-onset, high dose, and long duration of tramadol use. Scientific Significance This is the first study to investigate the co-occurrence of ADHD and tramadol misuse among adults.