Introduction The COVID-19 era has seen an increased trend in attention deficit hyperactivity disorder (ADHD) diagnoses. Historically, males have been diagnosed with ADHD more frequently than females during childhood. Studies have indicated a higher use of stimulant medications among male ADHD cases compared to females. This study examines ADHD cases from 2021 to 2023 to analyze yearly trends following the initial COVID-19 spike and explores gender and age differences between ADHD-positive and ADHD-negative cases. Methods This retrospective study was conducted using data from an urban outpatient mental health clinic in Alabama. Data were extracted from Electronic Health Records (EHR) for patients seen from January 1, 2021, to December 31, 2023. The Institutional Review Board (IRB) approved the study under the exempt research category. Data were analyzed using Microsoft Excel (Microsoft® Corp., Redmond, WA, USA) and the Statistical Package for the Social Sciences (IBM SPSS Statistics for Windows, IBM Corp., Version 26.0, Armonk, NY). Diagnoses were based on the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria, and clinical diagnoses and medication information were obtained from the EHR. Results The study included 1,422 patients, of whom 881 (62%) were diagnosed with ADHD. Females with ADHD had significantly higher comorbid conditions, such as major depressive disorder, generalized anxiety disorder, panic disorder, and post-traumatic stress disorder, compared to males with ADHD. Gender differences in ADHD diagnoses were seen over the years, though no significant age differences were observed. Conclusions The study indicates a sustained high rate of ADHD diagnoses even after the initial COVID-19 spike. Females showed a higher ADHD diagnoses compared to males, but stimulant medication use remained consistent across genders. No significant age differences were observed between males and females with ADHD. Further research is needed to explore the reasons behind these gender differences and to evaluate their implications.