Depression is a chronic and incapacitating mental health condition that is characterised by experience and poor regulation of low-mood, increased fatigue, feelings of guilt, worthlessness, helplessness, hopelessness, decreased appetite and sleep disturbances. With a global prevalence rate of 7% (Brody et al., 2018), depression is considered as a top contributor to global disability (WHO, 2017). Cognitive-behavioural therapy is considered to be the ‘gold- standard’ treatment amongst psychological interventions for treating depressive symptoms, however it takes a cross-sectional approach in treating the negative cognitions and associated changes in behaviours and emotions. With depression having one of the highest recurrence rate of 60%, the need to address underlying processes takes precedence. The Unified Protocol is a trans-diagnostics, emotion-focussed cognitive-behavioural therapy that incorporates several relevant cognitive-behavioural concepts to address the processes such as emotion-regulation strategies, experiential avoidance and poor distress tolerance that precipitate and maintain depressive episodes and further cause increased relapse rates. It further helps address the multitudes of comorbidities that depression manifests with such as anxiety and personality vulnerabilities. The present randomized controlled trial aims to study the efficacy of UP in addressing the depressive symptomatology and the underlying transdiagnostic, emotional processes by comparing the intervention and treatment as usual groups. The treatment as usual group is defined in this study as all OP based services including medication and unstructured therapy. The pilot phase of the study consisting of a sample of 4 individual, 2 in each group, will focus on the familiarization of the modality, finalizing the number of sessions required and administration of the tools. The main phase of the study has an estimated sample size of 35 in each group (the intervention and treatment as usual group) and the therapy sessions will be given weekly for 12-15 sessions for the intervention group. They will initially be screened using DIAMOND and SCID-V PD followed by the outcome and process measures which are Montgomery-Asberg Depression Rating Scale (MADRS), Center for Epidemiological Studies – Depression Scale (CES-D), Hamilton Anxiety Rating Scale (HAM-A), Acceptance and Action Questionnaire II (AAQ-II), Distress Tolerance Scale (DTS), Difficulties in Emotion Regulation Scale (DERS) Positive and Negative Affect Scale (PANAS), Cognitive Flexibility Inventory (CFI), The Shortened General Attitudes and Beliefs Scale (SGABS), The Working Alliance Inventory- Client Form(WAI) and the Client Change Interview. The primary outcome measure MADRS will be administered during the baseline, post-intervention and follow-up through an independent assessor who is blinded while the other measures will be administered in the baseline, midpoint (6th or 7th session), post-intervention and follow-up. A tailor-made visual mood analogue scale will be given for everyday administration and a brief rating-interview schedule will be used to assess the transdiagnostic variables emotion regulation, distress tolerance and experiential avoidance. The Data from each phase will be recorded, analyzed and interpreted using appropriate statistical methods with SPSS/R softwares. Post normality testing, linear-mixed model will be used, with P value less than 0.05 will being considered as statistically significant. Liner-mixed model will be used to assess change across different time points between the two study groups and Pearson’s correlation coefficient or Spearman’s Rho will be used to assess the correlation between quantitative variables. Appropriate referrals will be provided if the participant decides to drop out and requests alternative treatment.