Introduction. Physical therapy plays a significant role in managing frozen shoulder (FS), and it includes applying manual mobilization techniques to reduce pain, restore the extensibility of the shoulder capsule and increase range of motion (ROM). Objective: To compare the effectiveness of Gong's mobilization (GM) and Spencer technique (ST) in reducing pain, functional disability, and improving shoulder ROM on FS patients. Methods. A pre-and-post-test experimental study design was adopted, where thirty patients (n = 30) diagnosed with unilateral FS were selected and randomized into two groups of 15 using a simple random technique. Subjects in experimental group 1(EG-I) received ST technique and ultrasound therapy (US), with Codman's pendular exercise (CPE). Whereas experimental group II (EG-II) received GM technique and US, with CPE. The intervention lasted five days and consisted of one session every day. Three variables were assessed to study the treatment effectiveness both at the pre-intervention and at the end of the first week: (i) pain intensity as measured by the Visual Analogue Scale; (ii) shoulder ROM as measured by a goniometer (abduction, flexion, and medial rotation (MR)); and (iii) functional disability as measured by SPADI (Shoulder Pain Disability Index). Results. The EG-II showed a better reduction in pain intensity (mean difference (MD) of 0.87), SPADI (MD of 7), and increase in shoulder ROM (MD: 'abduction': 15.76; 'Flexion': 15.67; 'MR': 10.33) than the EG-I at 0.05 levels of significance. Conclusions. Gong's mobilization was found to be more effective than Spencer's technique with ultrasound therapy and CPE in treating patients with FS.