Introduction <p>This study aims to assess the structural features of adenoids and nasopharyngeal airways in boys with nonsyndromic unilateral complete cleft of lip and palate (UCLP group) compared to non-cleft lip and palate patients of the same age (control group), and to identify differences in the growth and development of adenoids and nasopharyngeal airways between two groups.</p> Methods <p>Adenoid and nasopharyngeal airway length, area, and volume were retrospectively analyzed using CBCT images (<i>n</i> = 120). The UCLP group comprised boys aged 6–11 with UCLP (<i>n</i> = 60), while the control group consisted of boys without cleft lip and palate (<i>n</i> = 60).</p> Results <p>Statistically significant differences (<i>p</i> &lt; 0.05) were observed between the UCLP group and the control group for adenoids, including the upper and lower parts of the adenoids, adenoid thickness, and adenoidal–nasopharyngeal ratio (ANR) values. In addition, significant differences (<i>p</i> &lt; 0.05) were found in the lower part of the nasopharyngeal airway, area of palatal plane, area of lower nasopharyngeal airway, and volume of lower nasopharyngeal airway.</p> Conclusions <p>UCLP boys aged 6–11 exhibit a broader nasopharyngeal airway, particularly in the palate and lower nasopharyngeal airway region, adenoid degeneration becomes more pronounced with age. When UCLP boys aged 6–11 experience adenoid hypertrophy, special attention should be given to the upper palatal plane and nasal ventilation. These factors should be the primary considerations when deciding whether to perform adenoidectomy. Similar to cephalometric X-ray films, utilizing CBCT image measurement to calculate ANR values can provide a more accurate method for evaluating adenoid size and nasopharyngeal airway obstruction in UCLP children.</p>