Predictable coverage of deep isolated mandibular gingival recessions is one of the most challenging endeavors in plastic-esthetic periodontal surgery, and limited data is available in the literature. The aim of this paper is to present the rationale, the step-by-step procedure, and the results obtained in a series of 24 patients treated by means of a novel surgical technique (the laterally closed tunnel [LCT]) specifically designed for deep isolated mandibular recessions. A total of 24 healthy patients (21 women and 3 men, mean age 25.75 ± 7.12 years) exhibiting one single deep mandibular Miller Class I (n = 4), II (n = 10), or III (n = 10) gingival recession ≥ 4 mm were consecutively treated with LCT in conjunction with an enamel matrix derivative (EMD) and palatal subepithelial connective tissue graft (SCTG). The following clinical parameters were assessed at baseline and 12 months postoperatively: probing depth (PD), clinical attachment level (CAL), complete root coverage (CRC), mean root coverage (MRC), recession depth (RD), and keratinized tissue width (KTW). The primary outcome variable was CRC. The postoperative morbidity was low, and no complications, such as bleeding, infections/abscesses, or loss of SCTG, occurred. At 12 months, CRC was obtained in 17 of the 24 defects (70.83%), while in the remaining 7 defects RC amounted to 80% to 90% (in 6 cases) and 79% (in 1 case). Of the 17 defects exhibiting CRC, 12 were central incisors and 5 were canines. With respect to defect type, CRC was found in 3 of the 4 Miller Class I, 8 of the 10 Class II, and in 6 of the 10 Class III defects. Mean RD changed from 5.14 ± 1.26 mm at baseline to 0.2 ± 0.37 mm at 12 months, while MRC amounted to 4.94 ± 1.19 mm, representing 96.11% (P .0001). Mean KTW increased from 1.41 ± 1.00 mm at baseline to 4.14 ± 1.67 mm (P .0001) at 12 months, yielding a KTW gain of 2.75 ± 1.52 (P .0001). No statistically significant changes in mean PD occurred following root coverage surgery (1.8 ± 0.2 mm at baseline and 2.1 ± 0.3 mm at 12 months). The present results suggest that the LCT is a valuable approach for the treatment of deep isolated mandibular Miller Class I, II, and III gingival recessions.