The aim of this study was to examine and compare the treatment effects of counselling in clients’ primary language and counselling with an interpreter. National Institute for Health and Care Excellence (NICE) guidance indicated that interpreters should be used when working with individuals whose primary language is not English. Following a pre-test post-test non-equivalent groups design, clients (N = 133) received counselling in their primary language or through an interpreter. Measures of depression (Patient Health Questionnaire; PHQ-9) and anxiety (Generalised Anxiety Disorder Scale; GAD-7) were completed pre- and post-treatment to examine treatment outcomes. Data were analyzed using a 2 (condition) x 2 (time) mixed design Analysis of Variance (ANOVA). There was no significant difference in treatment outcome between counselling in client’s primary language and interpreter facilitated counselling. Client satisfaction was rated high in both groups, and no significant difference was found. The findings suggest that interpreters can be used effectively when offering counselling to clients whose primary language is not English. Due to service provision, clients were not randomly allocated, and no control group was used.