diff --git a/README.md b/README.md
index 0c39ae45..dc1291ab 100644
--- a/README.md
+++ b/README.md
@@ -28,7 +28,7 @@ The project is currently alpha. While no breaking API changes are currently plan
 
 ### Overview
 
-This operator runs a Zookeeper 3.7.2 cluster, and uses Zookeeper dynamic reconfiguration to handle node membership.
+This operator runs a Zookeeper 3.9.3 cluster, and uses Zookeeper dynamic reconfiguration to handle node membership.
 
 The operator itself is built with the [Operator framework](https://github.com/operator-framework/operator-sdk).
 
diff --git a/docker/Dockerfile b/docker/Dockerfile
index 368f7a9d..155c7737 100644
--- a/docker/Dockerfile
+++ b/docker/Dockerfile
@@ -15,7 +15,7 @@ COPY zu /zu
 WORKDIR /zu
 RUN ./gradlew --console=verbose --info shadowJar
 
-FROM ${DOCKER_REGISTRY:+$DOCKER_REGISTRY/}zookeeper:3.7.2
+FROM ${DOCKER_REGISTRY:+$DOCKER_REGISTRY/}zookeeper:3.9.3
 COPY bin /usr/local/bin
 RUN chmod +x /usr/local/bin/*
 COPY --from=0 /zu/build/libs/zu.jar /opt/libs/
diff --git a/docker/zu/build.gradle.kts b/docker/zu/build.gradle.kts
index 32bc7820..f1c9030c 100644
--- a/docker/zu/build.gradle.kts
+++ b/docker/zu/build.gradle.kts
@@ -12,7 +12,7 @@ repositories {
 
 dependencies {
     implementation(kotlin("stdlib"))
-    implementation("org.apache.zookeeper:zookeeper:3.7.2")
+    implementation("org.apache.zookeeper:zookeeper:3.9.3")
 }
 
 tasks.withType<ShadowJar>() {