Lead acetate (PbAc) is one of the top five most dangerous toxic heavy metals, particularly leading to kidney damage and posing serious health risks in both humans and animals. Sinapic acid (SNP) is a naturally occurring flavonoid found in fruits and vegetables that stands out with its antioxidant, anti-inflammatory, and anticancer properties. This is the first study to investigate the effects of SNP on oxidative stress, inflammation, apoptosis, autophagy and endoplasmic reticulum (ER) stress in PbAc-induced nephrotoxicity in rats by biochemical, molecular and histological methods. 35 Spraque dawley rats were randomly divided into five groups of 7 rats each: control, PbAc, SNP (10mg/kg), PbAc + SNP 5, PbAC + SNP 10. PbAc at a dose of 30 mg/kg body weight was administered via oral gavage alone or in combination with SNP (5 and 10 mg/kg body weight) via oral gavage for seven days. While PbAc impaired renal function by increasing serum urea and creatinine levels, SNP decreased these levels and contributed to the improvement in renal function. The administration of SNP reduced oxidative stress by increasing PbAc-induced decreased antioxidant enzyme (SOD, CAT, and GPx) activities and GSH levels, decreasing MDA levels, a marker of increased lipid peroxidation. SNP administration reduced NF-κB, TNF-α, IL-1β, NLRP3, and RAGE mRNA transcription levels, NF-κB, and TNF-α protein levels that are among the PbAc-induced increased inflammation parameters. Decreases in antiapoptotic Bcl-2 and increases in apoptotic Bax, APAF-1, and Caspase-3 due to PbAc exposure, SNP reversed the situation. SNP reduced ER stress caused by PbAc by increasing PERK, IRE1, ATF-6, CHOP, and GRP-78 levels and made it tend to regress. SNP reduced autophagy damage by decreasing the Beclin-1 protein level increased by PbAc. The findings of the present study suggested that SNP attenuates PbAc-induced nephrotoxicity.