NIRS-KIT is a MATLAB toolbox for both task and resting-state fNIRS data analysis with a user-friendly GUI. This toolbox covers the entire analysis pipeline, including data preparation, quality check, preprocessing, individual-level analysis, group-level statistics, and result visualization. For task fNIRS data, individual-level analysis is carried out to detect task-related neural activation based on GLM. For resting-state fNIRS data, individual-level functional connectivity (FC), ALFF/fALFF, and network metrics can be calculated. For group-level analysis, NIRS-KIT provides several popular parametric models and multiple comparison correction approaches. NIRS-KIT provides multiple visualization functions to visualize the statistical results. Please contact: houxin195776@mail.bnu.edu.cn or zhzong@mail.bnu.edu.cn for it. NIRS-ICA, a toolbox for removing fNIRS noise and extracting neural activity-related sources, has been integrated into NIRS-KIT. Please contact: zhaoyang@mail.bnu.edu.cn for NIRS-ICA.