diff --git a/docs/codeql/reusables/supported-versions-compilers.rst b/docs/codeql/reusables/supported-versions-compilers.rst
index 93b826a94dd..da873041fb9 100644
--- a/docs/codeql/reusables/supported-versions-compilers.rst
+++ b/docs/codeql/reusables/supported-versions-compilers.rst
@@ -20,7 +20,7 @@
    Java,"Java 7 to 20 [4]_","javac (OpenJDK and Oracle JDK),
 
    Eclipse compiler for Java (ECJ) [5]_",``.java``
-   Kotlin [6]_,"Kotlin 1.5.0 to 1.8.20","kotlinc",``.kt``
+   Kotlin [6]_,"Kotlin 1.5.0 to 1.9.0","kotlinc",``.kt``
    JavaScript,ECMAScript 2022 or lower,Not applicable,"``.js``, ``.jsx``, ``.mjs``, ``.es``, ``.es6``, ``.htm``, ``.html``, ``.xhtm``, ``.xhtml``, ``.vue``, ``.hbs``, ``.ejs``, ``.njk``, ``.json``, ``.yaml``, ``.yml``, ``.raml``, ``.xml`` [7]_"
    Python [8]_,"2.7, 3.5, 3.6, 3.7, 3.8, 3.9, 3.10, 3.11",Not applicable,``.py``
    Ruby [9]_,"up to 3.2",Not applicable,"``.rb``, ``.erb``, ``.gemspec``, ``Gemfile``"
diff --git a/java/kotlin-extractor/build.py b/java/kotlin-extractor/build.py
index b52ff05b00e..2735f6af1c1 100755
--- a/java/kotlin-extractor/build.py
+++ b/java/kotlin-extractor/build.py
@@ -80,25 +80,37 @@ def run_process(cmd, capture_output=False):
                   errors='replace'), file=sys.stderr)
         raise e
 
+def write_arg_file(arg_file, args):
+    with open(arg_file, 'w') as f:
+        for arg in args:
+            if "'" in arg:
+                raise Exception('Single quote in argument: ' + arg)
+            f.write("'" + arg.replace('\\', '/') + "'\n")
 
-def compile_to_dir(srcs, classpath, java_classpath, output):
+def compile_to_dir(build_dir, srcs, classpath, java_classpath, output):
     # Use kotlinc to compile .kt files:
+    kotlin_arg_file = build_dir + '/kotlin.args'
+    kotlin_args = ['-Werror',
+                   '-opt-in=kotlin.RequiresOptIn',
+                   '-d', output,
+                   '-module-name', 'codeql-kotlin-extractor',
+                   '-no-reflect', '-no-stdlib',
+                   '-jvm-target', '1.8',
+                   '-classpath', classpath] + srcs
+    write_arg_file(kotlin_arg_file, kotlin_args)
     run_process([kotlinc,
-                 # kotlinc can default to 256M, which isn't enough when we are extracting the build
-                 '-J-Xmx2G',
-                 '-Werror',
-                 '-opt-in=kotlin.RequiresOptIn',
-                 '-d', output,
-                 '-module-name', 'codeql-kotlin-extractor',
-                 '-no-reflect', '-no-stdlib',
-                 '-jvm-target', '1.8',
-                 '-classpath', classpath] + srcs)
+                # kotlinc can default to 256M, which isn't enough when we are extracting the build
+                '-J-Xmx2G',
+                '@' + kotlin_arg_file])
 
     # Use javac to compile .java files, referencing the Kotlin class files:
-    run_process([javac,
-                 '-d', output,
+    java_arg_file = build_dir + '/java.args'
+    java_args = ['-d', output,
                  '-source', '8', '-target', '8',
-                 '-classpath', os.path.pathsep.join([output, classpath, java_classpath])] + [s for s in srcs if s.endswith(".java")])
+                 '-classpath', os.path.pathsep.join([output, classpath, java_classpath])] \
+              + [s for s in srcs if s.endswith(".java")]
+    write_arg_file(java_arg_file, java_args)
+    run_process([javac, '@' + java_arg_file])
 
 
 def compile_to_jar(build_dir, tmp_src_dir, srcs, classpath, java_classpath, output):
@@ -108,7 +120,7 @@ def compile_to_jar(build_dir, tmp_src_dir, srcs, classpath, java_classpath, outp
         shutil.rmtree(class_dir)
     os.makedirs(class_dir)
 
-    compile_to_dir(srcs, classpath, java_classpath, class_dir)
+    compile_to_dir(build_dir, srcs, classpath, java_classpath, class_dir)
 
     run_process(['jar', 'cf', output,
                  '-C', class_dir, '.',
diff --git a/java/kotlin-extractor/kotlin_plugin_versions.py b/java/kotlin-extractor/kotlin_plugin_versions.py
index 4583551e12d..c5d9e433613 100755
--- a/java/kotlin-extractor/kotlin_plugin_versions.py
+++ b/java/kotlin-extractor/kotlin_plugin_versions.py
@@ -25,7 +25,7 @@ def version_string_to_tuple(version):
 ci_version = '1.8.10'
 
 # Version numbers in the list need to be in semantically increasing order
-many_versions = [ '1.4.32', '1.5.0', '1.5.10', '1.5.20', '1.5.30', '1.6.0', '1.6.20', '1.7.0', '1.7.20', '1.8.0' ]
+many_versions = [ '1.4.32', '1.5.0', '1.5.10', '1.5.20', '1.5.30', '1.6.0', '1.6.20', '1.7.0', '1.7.20', '1.8.0', '1.9.0-Beta' ]
 
 many_versions_tuples = [version_string_to_tuple(v) for v in many_versions]
 
diff --git a/java/kotlin-extractor/src/main/kotlin/KotlinFileExtractor.kt b/java/kotlin-extractor/src/main/kotlin/KotlinFileExtractor.kt
index b93bfa369f5..a3bc20d9eda 100644
--- a/java/kotlin-extractor/src/main/kotlin/KotlinFileExtractor.kt
+++ b/java/kotlin-extractor/src/main/kotlin/KotlinFileExtractor.kt
@@ -366,7 +366,10 @@ open class KotlinFileExtractor(
 
             val typeArgs = removeOuterClassTypeArgs(c, argsIncludingOuterClasses)
             if (typeArgs != null) {
-                for ((idx, arg) in typeArgs.withIndex()) {
+                // From 1.9, the list might change when we call erase,
+                // so we make a copy that it is safe to iterate over.
+                val typeArgsCopy = typeArgs.toList()
+                for ((idx, arg) in typeArgsCopy.withIndex()) {
                     val argId = getTypeArgumentLabel(arg).id
                     tw.writeTypeArgs(argId, idx, id)
                 }
@@ -5531,7 +5534,7 @@ open class KotlinFileExtractor(
                         return
                     }
 
-                    val typeOwner = e.typeOperandClassifier.owner
+                    val typeOwner = e.typeOperand.classifierOrFail.owner
                     if (typeOwner !is IrClass) {
                         logger.errorElement("Expected to find SAM conversion to IrClass. Found '${typeOwner.javaClass}' instead. Can't implement SAM interface.", e)
                         return
diff --git a/java/ql/integration-tests/all-platforms/kotlin/diagnostics/kotlin-version-too-new/diagnostics.expected b/java/ql/integration-tests/all-platforms/kotlin/diagnostics/kotlin-version-too-new/diagnostics.expected
index 3397ea1bdef..36f7d9d0718 100644
--- a/java/ql/integration-tests/all-platforms/kotlin/diagnostics/kotlin-version-too-new/diagnostics.expected
+++ b/java/ql/integration-tests/all-platforms/kotlin/diagnostics/kotlin-version-too-new/diagnostics.expected
@@ -1,5 +1,5 @@
 {
-  "markdownMessage": "The Kotlin version installed (`999.999.999`) is too recent for this version of CodeQL. Install a version lower than 1.8.30.",
+  "markdownMessage": "The Kotlin version installed (`999.999.999`) is too recent for this version of CodeQL. Install a version lower than 1.9.10.",
   "severity": "error",
   "source": {
     "extractorName": "java",
diff --git a/java/ql/lib/change-notes/2023-05-24-kotlin-1.9.0.md b/java/ql/lib/change-notes/2023-05-24-kotlin-1.9.0.md
new file mode 100644
index 00000000000..f3647cc5488
--- /dev/null
+++ b/java/ql/lib/change-notes/2023-05-24-kotlin-1.9.0.md
@@ -0,0 +1,4 @@
+---
+category: feature
+---
+* Kotlin versions up to 1.9.0 are now supported.