Background: Deep neck infections (DNIs) are characterized by inflammation in the deep spaces and fasciae of the head and neck, with or without pus. Parapharyngeal, infratemporal, pterygomaxillary, temporal, parotid, masticator, submandibular, visceral, carotid sheath, peritonsillar-pharyngeal mucosal, retropharyngeal, danger, and prevertebral spaces are the different types of DNIs. These infections are potentially fatal, and they spread quickly, causing serious problems. Even in recent research on DNSI cases, potentially life-threatening complications have been recorded at a rate of 10%–20%. Objective: The objective of this study was to identify the most common organisms causing DNIs in Asir Central Hospital (ACH), Saudi Arabia in addition to identifying the most common sensitive antibiotic using to treat DNIs in ACH. Results: Data were retrieved from the records of 108 patients with DNIs (67.6% males, 91.7% Saudis). These included 23 patients in the pediatric group (21.3%) and 85 patients (78.7%) in the adult group. The most common sites for neck abscesses in the whole sample included the submandibular abscess (46.3%). Two types of DNIs were predominating in the pediatric group, including submandibular abscess and anterior neck abscess (30.4% for each type), while submandibular neck abscess was the most common type in the adult group (50.6%). Regarding the previous onset of a recent infection, a total of 67 infections were reported in 63 patients. Upper respiratory tract infections represented the majority of infectious conditions (77.6%) followed by dental infections (22.4%). Among the whole sample, the most commonly isolated pathogen was Staphylococcus species (n = 14, 13.0%), of which 12 Staphylococcus aureus isolates were detected. The 25 isolates with positive cultural growth had undergone culture sensitivity analysis; these showed sensitivity to 89 antibiotics. Bacterial isolates were predominantly sensitive to vancomycin (n = 16, 18.0%), linezolid (n = 14, 15.7%), and ciprofloxacin (n = 13, 14.6%). Conclusion: DNIs in children feature different characteristics from those in adults regarding severity and preceding illness. However, the causative microorganisms and antibiotics sensitivity were similar. S. aureus and vancomycin were the most common bacteria and sensitive antibiotic, respectively.