In this study, tragacanth gum/chitosan/ZnO nanoprism-based electrochemical sensors were prepared for sensing reactive dyes in water. To use an electrochemical sensor, a ~250 nm-sized ZnO nanoprism was synthesized via ultrasonic-assisted green synthesis method, using tragacanth gum and chitosan polymer blend as a matrix. The electrochemical properties of tragacanth gum/chitosan/ZnO nanoprisms were compared against reactive red 35, reactive yellow 15, and reactive black 194. The electrochemical measurement results indicated that prepared tragacanth gum/chitosan/ZnO nanoprism-based electrochemical sensor detected 25 ppm reactive red 35 in 1 min at room temperature. This study reveals new high-potential novel tragacanth gum/chitosan/ZnO nanoprism-based sensing material for the detection of reactive red dye-consisted wastewater with high sensitivity and short response time.