Increasing soil salinity in some agricultural areas due to global climate change is an obstacle in horticultural crop cultivation. Chili pepper (Capsicum frutescens L.) is an important horticultural crop that has high economic values but the extensive cultivation in saline land can reduce yields. Plant tolerance must be increased to be able to adapt in salinity stress conditions. One method that can be used is seed priming, which is pre-soaking the seeds to increase germination under unfavourable conditions. This study aimed to determine the effect of seed osmopriming using PEG 6000 on growth and physiological responses of chili pepper under salinity stress. The experimental design of this study included two factors: concentration of PEG 6000 (0, 12.5 and 25%) and salinity stress of 0, 2000, and 4000 ppm of NaCl. The observed parameters were 1) germination (percentage and rate of germination, germination synchronization); 2) growth (plant height; root length; dry weight of roots and shoot, number of fruits, fruit weight and capsaicin level); 3) physiological analysis (chlorophyll and proline levels). Seed osmopriming with 25% of PEG 6000 increased germination and plant growth of chili pepper under salinity stress conditions. Chlorophyll level increased while proline and capsaicin level decreased on osmopriming with 25% of PEG 6000. By studying the growth and physiological responses of chili pepper under salinity stress, the role of osmopriming in reducing the harmful effects of salinity stress can be determined.