Background: In response to the stresses of the contemporary workplace, the challenges of maintaining satisfactory work-life balance, and the costs to business of employee mental health problems, many organisations have contracted to make counselling services available to their staff. It is essential to evaluate the effectiveness of workplace counselling, in order to maintain standards, and to identify examples of good practice. Objectives: This paper presents a comprehensive, systematic review of the effectiveness of workplace counselling. Findings are analysed in terms of client satisfaction, psychological functioning, the meaning of work, work behaviour, and negative outcomes. Findings: Taken as a whole, the results of research suggest that counselling is generally effective in alleviating psychological problems, has a significant impact on sickness absence, and has a moderate effect on attitudes to work. Discussion: Methodological issues are discussed, and it is recommended that more high-quality research is required in order to reinforce the evidence base for workplace counselling in relation to a number of key questions.