Objectives: The aim of the present study is to confirm the efficacy, safety, and cost-effectiveness of thread-embedding acupuncture (TEA) in the treatment of adhesive capsulitis (AC). Methods: This is a randomized, sham-controlled, patient-assessor blinded trial with two parallel arms in a 1:1 ratio. A total of 160 participants with AC, also known as frozen shoulder, will be recruited and screened according to the eligibility criteria. Those who meet the eligibility criteria will be randomly allocated to a TEA group or a sham TEA (STEA) group. Both groups will receive either real TEA or thread-removed STEA treatment on nine acupoints once a week for 8 weeks while being blinded to the intervention. The shoulder pain and disability index will be evaluated as a primary outcome measure. In addition, a 100-mm pain visual analogue scale, rotator cuff quality of life scale, European Quality of Life 5-dimension 5-level scale, treatment satisfaction, safety assessment, and economic evaluation will be assessed as secondary outcome measures. Outcome assessments will be conducted for a total of 24 weeks, including a treatment period of 8 weeks and follow-up of 16 weeks, according to the schedule. Discussion: The results of this trial will provide a clinical basis for the efficacy, safety and cost-effectiveness of TEA in the treatment of patients with AC.