While potential costs and tracked spending on adaptation to climate change in middle-income countries (MICs) are difficult to measure, there is wide agreement that current spending on adaption is highly inadequate. This helpdesk report examines if there is evidence that there is a need for MICs to invest more than they currently do in climate change adaptation. It also looks at the main likely human and economic costs if MICs fail to do so considering how poor and vulnerable groups are affected. Overall, evidence on the costs of adaptation and tracked spending across possible sources of funding is minimal. Despite these limitations, three cross-cutting themes have been identified that are either partly supported by empirical evidence or are widely supported by leading institutions or climate finance experts.