<p>Lithium–sulfur (Li–S) batteries have attracted worldwide attention due to their high theoretical energy density of 2600 Wh kg⁻¹. However, their actual performances are severely hindered by the complicated electrochemical processes featuring sluggish cathode kinetics, unstable anode interfaces, and inter-electrode side reactions. Electrochemical testing constitutes a core tool for mechanism investigation and performance evaluation on the above processes. Herein, a comprehensive summary of basic electrochemical testing in Li–S batteries is provided, aiming to establish a standardized testing guideline for both experimental practices and data interpretation. Electrochemical methods for assessing the reaction kinetics of sulfur cathode and the stability of lithium anode are outlined. Standard configurations and performance evaluation metrics for Li–S batteries, encompassing both coin and pouch cells, are recommended to ensure experimental consistency and support comparison across different researches. This manuscript affords a basic electrochemical testing guidance for Li–S batteries, encourages standardization in experimental design and interpretation, and is expected to facilitate the development and application of Li–S battery technology.</p> Graphical abstract <p>Electrochemical testing methods in lithium–sulfur batteries.</p>