diff --git a/.github/actions/setup-effekt/action.yml b/.github/actions/setup-effekt/action.yml
index 5a0dfee26..2730c730b 100644
--- a/.github/actions/setup-effekt/action.yml
+++ b/.github/actions/setup-effekt/action.yml
@@ -13,7 +13,7 @@ inputs:
   llvm-version:
     description: 'LLVM version to install'
     required: false
-    default: '15'
+    default: '18'
   install-dependencies:
     description: 'Whether to install system dependencies (Linux only)'
     required: false
diff --git a/effekt/jvm/src/main/scala/effekt/EffektConfig.scala b/effekt/jvm/src/main/scala/effekt/EffektConfig.scala
index 9fba7dd6d..4f68a3547 100644
--- a/effekt/jvm/src/main/scala/effekt/EffektConfig.scala
+++ b/effekt/jvm/src/main/scala/effekt/EffektConfig.scala
@@ -68,8 +68,8 @@ class EffektConfig(args: Seq[String]) extends REPLConfig(args.takeWhile(_ != "--
 
   val llvmVersion: ScallopOption[String] = opt[String](
     "llvm-version",
-    descr = "the llvm version that should be used to compile the generated programs (only necessary if backend is llvm, defaults to 15)",
-    default = Some(sys.env.getOrElse("EFFEKT_LLVM_VERSION", "15")),
+    descr = "the llvm version that should be used to compile the generated programs (only necessary if backend is llvm, defaults to 18)",
+    default = Some(sys.env.getOrElse("EFFEKT_LLVM_VERSION", "18")),
     noshort = true,
     group = advanced
   )
diff --git a/effekt/jvm/src/main/scala/effekt/Runner.scala b/effekt/jvm/src/main/scala/effekt/Runner.scala
index 33afd4d0a..994214b48 100644
--- a/effekt/jvm/src/main/scala/effekt/Runner.scala
+++ b/effekt/jvm/src/main/scala/effekt/Runner.scala
@@ -267,8 +267,8 @@ object LLVMRunner extends Runner[String] {
   override def includes(path: File): List[File] = List(path / ".." / "llvm")
 
   lazy val gccCmd = discoverExecutable(List("cc", "clang", "gcc"), List("--version"))
-  lazy val llcCmd = discoverExecutable(List("llc", "llc-15", "llc-16"), List("--version"))
-  lazy val optCmd = discoverExecutable(List("opt", "opt-15", "opt-16"), List("--version"))
+  lazy val llcCmd = discoverExecutable(List("llc", "llc-18"), List("--version"))
+  lazy val optCmd = discoverExecutable(List("opt", "opt-18"), List("--version"))
 
   def checkSetup(): Either[String, Unit] =
     gccCmd.getOrElseAborting { return Left("Cannot find gcc. This is required to use the LLVM backend.") }