Background There is growing interest in paying for performance (P4P) as a means to align the incentives of healthcare providers with public health goals. Rigorous evidence on the effectiveness of these strategies in improving health care and health in low‐ and middle‐income countries (LMICs) is lacking; this is an update of the 2012 review on this topic. Objectives To assess the effects of paying for performance on the provision of health care and health outcomes in low‐ and middle‐income countries. Search methods We searched CENTRAL, MEDLINE, Embase, and 10 other databases between April and June 2018. We also searched two trial registries, websites, online resources of international agencies, organizations and universities, and contacted experts in the field. Studies identified from rerunning searches in 2020 are under 'Studies awaiting classification.' Selection criteria We included randomized or non‐randomized trials, controlled before‐after studies, or interrupted time series studies conducted in LMICs (as defined by the World Bank in 2018). P4P refers to the transfer of money or material goods conditional on taking a measurable action or achieving a predetermined performance target. To be included, a study had to report at least one of the following outcomes: patient health outcomes, changes in targeted measures of provider performance (such as the delivery of healthcare services), unintended effects, or changes in resource use. Data collection and analysis We extracted data as per original review protocol and narratively synthesised findings. We used standard methodological procedures expected by Cochrane. Given diversity and variability in intervention types, patient populations, analyses and outcome reporting, we deemed meta‐analysis inappropriate. We noted the range of effects associated with P4P against each outcome of interest. Based on intervention descriptions provided in documents, we classified design schemes and explored variation in effect by scheme design. Main results We included 59 studies: controlled before‐after studies (19), non‐randomized (16) or cluster randomized trials (14); and interrupted time‐series studies (9). One study included both an interrupted time series and a controlled before‐after study. Studies focused on a wide range of P4P interventions, including target payments and payment for outputs as modified by quality (or quality and equity assessments). Only one study assessed results‐based aid. Many schemes were funded by national governments (23 studies) with the World Bank funding most externally funded schemes (11 studies). Targeted services varied; however, most interventions focused on reproductive, maternal and child health indicators. Participants were predominantly located in public or in a mix of public, non‐governmental and faith‐based facilities (54 studies). P4P was assessed predominantly at health facility level, though districts and other levels were also involved. Most studies assessed the effects of P4P against a status quo control (49 studies); however, some studies assessed effects against comparator interventions (predominantly enhanced financing intended to match P4P funds (17 studies)). Four studies reported intervention effects against both comparator and status quo. Controlled before‐after studies were at higher risk of bias than other study designs. However, some randomised trials were also downgraded due to risk of bias. The interrupted time‐series studies provided insufficient information on other concurrent changes in the study context. P4P compared to a status quo control For health services that are specifically targeted, P4P may slightly improve health outcomes (low certainty evidence), but few studies assessed this. P4P may also improve service quality overall (low certainty evidence); and probably increases the availability of health workers, medicines and well‐functioning infrastructure and equipment (moderate certainty evidence). P4P may have mixed effects on the delivery and use of services (low certainty evidence) and may have few or no distorting unintended effects on outcomes that were not targeted (low‐certainty evidence), but few studies assessed these. For secondary outcomes, P4P may make little or no difference to provider absenteeism, motivation or satisfaction (low certainty evidence); but may improve patient satisfaction and acceptability (low certainty evidence); and may positively affect facility managerial autonomy (low certainty evidence). P4P probably makes little to no difference to management quality or facility governance (low certainty evidence). Impacts on equity were mixed (low certainty evidence). For health services that are untargeted, P4P probably improves some health outcomes (moderate certainty evidence); may improve the delivery, use and quality of some health services but may make little or no difference to others (low certainty evidence); and may have few or no distorting unintended effects (low certainty evidence). The effects of P4P on the availability of medicines and other resources are uncertain (very low certainty evidence). P4P compared to other strategies For health outcomes and services that are specifically targeted, P4P may make little or no difference to health outcomes (low certainty evidence), but few studies assessed this. P4P may improve service quality (low certainty evidence); and may have mixed effects on the delivery and use of health services and on the availability of equipment and medicines (low certainty evidence). For health outcomes and services that are untargeted, P4P may make little or no difference to health outcomes and to the delivery and use of health services (low certainty evidence). The effects of P4P on service quality, resource availability and unintended effects are uncertain (very low certainty evidence). Findings of subgroup analyses Results‐based aid, and schemes using payment per output adjusted for service quality, appeared to yield the greatest positive effects on outcomes. However, only one study evaluated results‐based aid, so the effects may be spurious. Overall, schemes adjusting both for quality of service and rewarding equitable delivery of services appeared to perform best in relation to service utilization outcomes. Authors' conclusions The evidence base on the impacts of P4P schemes has grown considerably, with study quality gradually increasing. P4P schemes may have mixed effects on outcomes of interest, and there is high heterogeneity in the types of schemes implemented and evaluations conducted. P4P is not a uniform intervention, but rather a range of approaches. Its effects depend on the interaction of several variables, including the design of the intervention (e.g., who receives payments ), the amount of additional funding, ancillary components (such as technical support) and contextual factors (including organizational context)., Plain language summary Paying for performance to improve the delivery of healthcare services in low‐ and middle‐income countries The aim of this Cochrane Review was to assess the effects of ‘pay for performance’ on the delivery of healthcare services in low‐ and middle‐income countries. The review authors collected and analysed all relevant studies to answer this question and found 59 studies. Key messages The studies included in this review looked at pay for performance approaches that varied in their design, setting and implementation. The review shows that pay for performance may have both positive and negative effects on the health services it targets. It may also have positive effects on other health services that are not directly targeted and may have no unintended negative effects on these services. However, most of this evidence is of low certainty and we need more, well‐conducted studies on this topic. What is ‘pay for performance’? In a 'pay for performance' approach, people are given money or other rewards if they carry out a particular task or meet a particular target. Pay for performance is usually directed at health workers or healthcare facilities. The health workers or healthcare facilities are rewarded if they offer particular services or deliver care that is of a certain quality, or if their patients use particular services and achieve better health as a result. Pay for performance can be used to target specific health problems and services that need improvement. But pay for performance could also affect other services that are not specifically targeted. For instance, it could lead health workers to improve the quality of the other services they deliver. But it could also lead them to avoid services that don’t lead to extra payment. To find out more, the review authors assessed the effects of paying for performance on both targeted and untargeted services. This included looking for any unintended effects. What are the main results of the review? The review included 59 relevant studies. Most were from sub‐Saharan Africa and Asia. Most of the pay for performance schemes in the studies were funded by national Ministries of Health, also with support of the World Bank. Forty‐nine studies compared health facilities that used pay for performance with health facilities that were doing business as usual. Seventeen studies compared health facilities that used pay for performance with facilities that used other approaches. In most of these studies, these approaches involved giving similar amount of funds but without insisting on a pay for performance element. The effects of paying for performance compared to business as usual For health services that are specifically targeted, pay for performance: ‐ may improve some health outcomes, may improve service quality and probably increase the availability of health workers, medicines and well‐functioning infrastructure and equipment; but ‐ may have both positive and negative effects on the delivery and use of health services. For health services that are untargeted, pay for performance: ‐ probably improves some health outcomes; ‐ may improve the delivery, use and quality of some health services but may make little or no difference to others; and ‐ may have few or no unintended effects. We don’t know what the effects of pay for performance are on the availability of medicines and other resources because the evidence was of very low certainty The effects of paying for performance compared to other approaches For health outcomes and services that are specifically targeted, pay for performance: ‐ may improve service quality; ‐ may make little or no difference to health outcomes; and ‐ may have both positive and negative on the delivery and use of health services and on the availability of equipment and medicines. For health outcomes and services that are untargeted, pay for performance: ‐ may make little or no difference to health outcomes and to the delivery and use of health services. We don’t know what the effects of pay for performance are on service quality, on the availability of resources, and on unintended effects because the evidence was missing or of very low certainty How up to date is this review? The review authors included studies that had been published up to April 2018.