To inform the UK Government’s smart energy policy, the Department for Business, Energy and Industrial Strategy (BEIS) contracted E4tech to undertake a comprehensive evidence assessment of small-scale Demand-Side Response (DSR). The study focused on drawing out findings relevant to Great Britain, drawing on a wide range of UK and international evidence. The objective was to identify the market, policy, commercial, and consumer factors that enable successful DSR at small scale and thereby build a robust evidence base for DSR policy. Supported by an academic consortium, E4tech conducted a comprehensive and structured literature review of existing evidence and conducted interviews with 30 industry experts in Finland, Norway, Germany, Illinois and Texas. The study provided novel insights to the various factors leading to successful DSR markets.