diff --git a/build.gradle.kts b/build.gradle.kts
index c871a1ca6..6af9a7196 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -1,5 +1,5 @@
 plugins {
-    val kotlinVersion = "1.8.20"
+    val kotlinVersion = "1.9.20"
     id("com.android.application") version "7.4.2" apply (false)
     id("org.jetbrains.kotlin.android") version kotlinVersion apply (false)
     id("org.jetbrains.kotlin.kapt") version kotlinVersion apply (false)
diff --git a/uhabits-android/build.gradle.kts b/uhabits-android/build.gradle.kts
index ac7b5cfaf..814d8fba8 100644
--- a/uhabits-android/build.gradle.kts
+++ b/uhabits-android/build.gradle.kts
@@ -94,7 +94,7 @@ android {
 
 dependencies {
     val daggerVersion = "2.48.1"
-    val kotlinVersion = "1.8.20"
+    val kotlinVersion = "1.9.20"
     val kxCoroutinesVersion = "1.7.3"
     val ktorVersion = "1.6.8"
     val espressoVersion = "3.5.1"
diff --git a/uhabits-server/build.gradle.kts b/uhabits-server/build.gradle.kts
index c5434de6d..63daff801 100644
--- a/uhabits-server/build.gradle.kts
+++ b/uhabits-server/build.gradle.kts
@@ -38,7 +38,7 @@ application {
 
 dependencies {
     val ktorVersion = "1.6.8"
-    val kotlinVersion = "1.8.20"
+    val kotlinVersion = "1.9.20"
     val logbackVersion = "1.4.9"
     implementation("org.jetbrains.kotlin:kotlin-stdlib-jdk8:$kotlinVersion")
     implementation("io.ktor:ktor-server-netty:$ktorVersion")