diff --git a/integration-tests/cli/src/integrationTest/kotlin/org/jetbrains/dokka/it/cli/CliIntegrationTest.kt b/integration-tests/cli/src/integrationTest/kotlin/org/jetbrains/dokka/it/cli/CliIntegrationTest.kt
index 8fdcaad5a8..05ef667ab8 100644
--- a/integration-tests/cli/src/integrationTest/kotlin/org/jetbrains/dokka/it/cli/CliIntegrationTest.kt
+++ b/integration-tests/cli/src/integrationTest/kotlin/org/jetbrains/dokka/it/cli/CliIntegrationTest.kt
@@ -147,4 +147,38 @@ class CliIntegrationTest : AbstractCliIntegrationTest() {
             "Expected to render empty packages"
         )
     }
+
+    @Test
+    fun `module name should be optional`() {
+        val dokkaOutputDir = File(projectDir, "output")
+        assertTrue(dokkaOutputDir.mkdirs())
+        val process = ProcessBuilder(
+            "java", "-jar", cliJarFile.path,
+            "-outputDir", dokkaOutputDir.path,
+            "-pluginsClasspath", basePluginJarFile.path,
+            "-sourceSet",
+            buildString {
+                append(" -src ${File(projectDir, "src").path}")
+            }
+        )
+            .redirectErrorStream(true)
+            .start()
+
+        val result = process.awaitProcessResult()
+        assertEquals(0, result.exitCode, "Expected exitCode 0 (Success)")
+
+        assertTrue(dokkaOutputDir.isDirectory, "Missing dokka output directory")
+
+        val imagesDir = File(dokkaOutputDir, "images")
+        assertTrue(imagesDir.isDirectory, "Missing images directory")
+
+        val scriptsDir = File(dokkaOutputDir, "scripts")
+        assertTrue(scriptsDir.isDirectory, "Missing scripts directory")
+
+        val stylesDir = File(dokkaOutputDir, "styles")
+        assertTrue(stylesDir.isDirectory, "Missing styles directory")
+
+        val navigationHtml = File(dokkaOutputDir, "navigation.html")
+        assertTrue(navigationHtml.isFile, "Missing navigation.html")
+    }
 }
diff --git a/runners/cli/src/main/kotlin/cli/main.kt b/runners/cli/src/main/kotlin/cli/main.kt
index 7c402df5e3..36edb2d945 100644
--- a/runners/cli/src/main/kotlin/cli/main.kt
+++ b/runners/cli/src/main/kotlin/cli/main.kt
@@ -74,7 +74,7 @@ class GlobalArguments(args: Array<String>) : DokkaConfiguration {
         description = "Document generated or obvious functions like default `toString` or `equals`"
     ).default(!DokkaDefaults.suppressObviousFunctions)
 
-    override val suppressObviousFunctions: Boolean by lazy{ !noSuppressObviousFunctions }
+    override val suppressObviousFunctions: Boolean by lazy { !noSuppressObviousFunctions }
 
     private val _includes by parser.option(
         ArgTypeFile,
@@ -316,7 +316,13 @@ object ArgTypeSourceLinkDefinition : ArgType<DokkaConfiguration.SourceLinkDefini
 data class ArgTypeArgument(val moduleName: CLIEntity<kotlin.String>) :
     ArgType<DokkaConfiguration.DokkaSourceSet>(true) {
     override fun convert(value: kotlin.String, name: kotlin.String): DokkaConfiguration.DokkaSourceSet =
-        parseSourceSet(moduleName.value, value.split(" ").filter { it.isNotBlank() }.toTypedArray())
+        (if (moduleName.valueOrigin != ArgParser.ValueOrigin.UNSET && moduleName.valueOrigin != ArgParser.ValueOrigin.UNDEFINED) {
+            moduleName.value
+        } else {
+            DokkaDefaults.moduleName
+        }).let { moduleNameOrDefault ->
+            parseSourceSet(moduleNameOrDefault, value.split(" ").filter { it.isNotBlank() }.toTypedArray())
+        }
 
     override val description: kotlin.String
         get() = ""