This systematic literature review (SLR) aimed to identify and evaluate existing indirect treatment comparison (ITC) techniques, providing a comprehensive description of each method and assessing their strengths and limitations from a health technology assessment (HTA) perspective. The review was conducted in accordance with PRISMA guidelines, using electronic databases (Embase and PubMed) and grey literature searches up to November 15, 2021. Eligible articles were peer-reviewed papers describing different ITC techniques in English. A total of 73 articles were included, reporting seven different ITC techniques: network meta-analysis (NMA), matching-adjusted indirect comparison (MAIC), network meta-regression (NMR), the Bucher method, simulated treatment comparison (STC), propensity score matching (PSM), and inverse probability of treatment weighting (IPTW). Network meta-analysis was the most frequently described technique (79.5%), followed by MAIC (30.1%) and NMR (24.7%). The choice of ITC technique is critical and depends on factors such as the feasibility of a connected network, evidence of heterogeneity, the number of relevant studies, and the availability of individual patient-level data (IPD). MAIC and STC are common in single-arm studies, while the Bucher method and NMA are suitable when IPD are not available. The review highlights the need for clearer international consensus and guidance on ITC techniques to improve the quality of submissions to HTA agencies.This systematic literature review (SLR) aimed to identify and evaluate existing indirect treatment comparison (ITC) techniques, providing a comprehensive description of each method and assessing their strengths and limitations from a health technology assessment (HTA) perspective. The review was conducted in accordance with PRISMA guidelines, using electronic databases (Embase and PubMed) and grey literature searches up to November 15, 2021. Eligible articles were peer-reviewed papers describing different ITC techniques in English. A total of 73 articles were included, reporting seven different ITC techniques: network meta-analysis (NMA), matching-adjusted indirect comparison (MAIC), network meta-regression (NMR), the Bucher method, simulated treatment comparison (STC), propensity score matching (PSM), and inverse probability of treatment weighting (IPTW). Network meta-analysis was the most frequently described technique (79.5%), followed by MAIC (30.1%) and NMR (24.7%). The choice of ITC technique is critical and depends on factors such as the feasibility of a connected network, evidence of heterogeneity, the number of relevant studies, and the availability of individual patient-level data (IPD). MAIC and STC are common in single-arm studies, while the Bucher method and NMA are suitable when IPD are not available. The review highlights the need for clearer international consensus and guidance on ITC techniques to improve the quality of submissions to HTA agencies.