diff --git a/core/src/main/java/com/facebook/ktfmt/cli/ParsedArgs.kt b/core/src/main/java/com/facebook/ktfmt/cli/ParsedArgs.kt
index 069ea5fc..b2ed16d5 100644
--- a/core/src/main/java/com/facebook/ktfmt/cli/ParsedArgs.kt
+++ b/core/src/main/java/com/facebook/ktfmt/cli/ParsedArgs.kt
@@ -60,30 +60,30 @@ data class ParsedArgs(
         |formatting succeeded or failed on standard error. If none of the style options are
         |passed, Meta's style is used.
         |
-        |Alternatively, ktfmt can read Kotlin source code from standard input and write the 
+        |Alternatively, ktfmt can read Kotlin source code from standard input and write the
         |formatted result on standard output.
         |
         |Example:
         |     $ ktfmt --kotlinlang-style Main.kt src/Parser.kt
         |     Done formatting Main.kt
         |     Error formatting src/Parser.kt: @@@ERROR@@@; skipping.
-        |    
+        |
         |Commands options:
         |  -h, --help                        Show this help message
-        |  -n, --dry-run                     Don't write to files, only report files which 
+        |  -n, --dry-run                     Don't write to files, only report files which
         |                                        would have changed
         |  --meta-style                      Use 2-space block indenting (default)
         |  --google-style                    Google internal style (2 spaces)
         |  --kotlinlang-style                Kotlin language guidelines style (4 spaces)
         |  --stdin-name=<name>               Name to report when formatting code from stdin
-        |  --set-exit-if-changed             Sets exit code to 1 if any input file was not 
+        |  --set-exit-if-changed             Sets exit code to 1 if any input file was not
         |                                        formatted/touched
         |  --do-not-remove-unused-imports    Leaves all imports in place, even if not used
-        |  
+        |
         |ARGFILE:
         |  If the only argument begins with '@', the remainder of the argument is treated
         |  as the name of a file to read options and arguments from, one per line.
-        |  
+        |
         |  e.g.
         |      $ cat arg-file.txt
         |      --google-style
@@ -109,9 +109,21 @@ data class ParsedArgs(
 
       for (arg in args) {
         when {
-          arg == "--meta-style" -> formattingOptions = Formatter.META_FORMAT
-          arg == "--google-style" -> formattingOptions = Formatter.GOOGLE_FORMAT
-          arg == "--kotlinlang-style" -> formattingOptions = Formatter.KOTLINLANG_FORMAT
+          arg.startsWith("--style=") -> {
+            val parsedStyle =
+              parseKeyValueArg("--style", arg)
+                ?: return ParseResult.Error(
+                  unexpectedArg(arg)
+                )
+            formattingOptions = when (parsedStyle) {
+              "meta" -> Formatter.META_FORMAT
+              "google" -> Formatter.GOOGLE_FORMAT
+              "kotlinlang" -> Formatter.KOTLINLANG_FORMAT
+              else -> return ParseResult.Error(
+                "Unknown style '${parsedStyle}'. Style must be one of [dropbox, google, kotlinlang]."
+              )
+            }
+          }
           arg == "--dry-run" || arg == "-n" -> dryRun = true
           arg == "--set-exit-if-changed" -> setExitIfChanged = true
           arg == "--do-not-remove-unused-imports" -> removeUnusedImports = false
@@ -120,8 +132,8 @@ data class ParsedArgs(
                   parseKeyValueArg("--stdin-name", arg)
                       ?: return ParseResult.Error(
                           "Found option '${arg}', expected '${"--stdin-name"}=<value>'")
-          arg.startsWith("--") -> return ParseResult.Error("Unexpected option: $arg")
-          arg.startsWith("@") -> return ParseResult.Error("Unexpected option: $arg")
+          arg.startsWith("--") -> return ParseResult.Error(unexpectedArg(arg))
+          arg.startsWith("@") -> return ParseResult.Error(unexpectedArg(arg))
           else -> fileNames.add(arg)
         }
       }
@@ -148,6 +160,8 @@ data class ParsedArgs(
           ))
     }
 
+    private fun unexpectedArg(arg: String) = "Unexpected option: $arg"
+
     private fun parseKeyValueArg(key: String, arg: String): String? {
       val parts = arg.split('=', limit = 2)
       return parts[1].takeIf { parts[0] == key || parts.size == 2 }
diff --git a/core/src/test/java/com/facebook/ktfmt/cli/MainTest.kt b/core/src/test/java/com/facebook/ktfmt/cli/MainTest.kt
index a2adbc44..31cc47a5 100644
--- a/core/src/test/java/com/facebook/ktfmt/cli/MainTest.kt
+++ b/core/src/test/java/com/facebook/ktfmt/cli/MainTest.kt
@@ -225,7 +225,7 @@ class MainTest {
   }
 
   @Test
-  fun `kotlinlang-style is passed to formatter (file)`() {
+  fun `--style=kotlinlang is passed to formatter (file)`() {
     val code =
         """fun f() {
     for (child in
@@ -241,14 +241,14 @@ class MainTest {
             emptyInput,
             PrintStream(out),
             PrintStream(err),
-            arrayOf("--kotlinlang-style", fooBar.toString()))
+            arrayOf("--style=kotlinlang", fooBar.toString()))
         .run()
 
     assertThat(fooBar.readText()).isEqualTo(code)
   }
 
   @Test
-  fun `kotlinlang-style is passed to formatter (stdin)`() {
+  fun `--style=kotlinlang is passed to formatter (stdin)`() {
     val code =
         """fun f() {
           |for (child in
@@ -271,7 +271,7 @@ class MainTest {
             code.byteInputStream(),
             PrintStream(out),
             PrintStream(err),
-            arrayOf("--kotlinlang-style", "-"))
+            arrayOf("--style=kotlinlang", "-"))
         .run()
 
     assertThat(out.toString(UTF_8)).isEqualTo(formatted)
diff --git a/core/src/test/java/com/facebook/ktfmt/cli/ParsedArgsTest.kt b/core/src/test/java/com/facebook/ktfmt/cli/ParsedArgsTest.kt
index cac9cc12..6d5fbbc9 100644
--- a/core/src/test/java/com/facebook/ktfmt/cli/ParsedArgsTest.kt
+++ b/core/src/test/java/com/facebook/ktfmt/cli/ParsedArgsTest.kt
@@ -61,23 +61,29 @@ class ParsedArgsTest {
   }
 
   @Test
-  fun `parseOptions recognizes --meta-style`() {
-    val parsed = assertSucceeds(ParsedArgs.parseOptions(arrayOf("--meta-style", "foo.kt")))
+  fun `parseOptions recognizes --style=meta`() {
+    val parsed = assertSucceeds(ParsedArgs.parseOptions(arrayOf("--style=meta", "foo.kt")))
     assertThat(parsed.formattingOptions).isEqualTo(Formatter.META_FORMAT)
   }
 
   @Test
-  fun `parseOptions recognizes --dropbox-style`() {
-    val parsed = assertSucceeds(ParsedArgs.parseOptions(arrayOf("--kotlinlang-style", "foo.kt")))
+  fun `parseOptions recognizes --style=kotlinlang`() {
+    val parsed = assertSucceeds(ParsedArgs.parseOptions(arrayOf("--style=kotlinlang", "foo.kt")))
     assertThat(parsed.formattingOptions).isEqualTo(Formatter.KOTLINLANG_FORMAT)
   }
 
   @Test
-  fun `parseOptions recognizes --google-style`() {
-    val parsed = assertSucceeds(ParsedArgs.parseOptions(arrayOf("--google-style", "foo.kt")))
+  fun `parseOptions recognizes --style=google`() {
+    val parsed = assertSucceeds(ParsedArgs.parseOptions(arrayOf("--style=google", "foo.kt")))
     assertThat(parsed.formattingOptions).isEqualTo(Formatter.GOOGLE_FORMAT)
   }
 
+  @Test
+  fun `parseOptions rejects unknown style`() {
+    val parseResult = ParsedArgs.parseOptions(arrayOf("--style=custom-style", "foo.kt"))
+    assertThat(parseResult).isInstanceOf(ParseResult.Error::class.java)
+  }
+
   @Test
   fun `parseOptions recognizes --dry-run`() {
     val parsed = assertSucceeds(ParsedArgs.parseOptions(arrayOf("--dry-run", "foo.kt")))
@@ -170,7 +176,7 @@ class ParsedArgsTest {
   @Test
   fun `processArgs use the @file option with file containing arguments`() {
     val file = root.resolve("existing-file")
-    file.writeText("--google-style\n--dry-run\n--set-exit-if-changed\nFile1.kt\nFile2.kt\n")
+    file.writeText("--style=google\n--dry-run\n--set-exit-if-changed\nFile1.kt\nFile2.kt\n")
 
     val result = ParsedArgs.processArgs(arrayOf("@" + file.absolutePath))
     assertThat(result).isInstanceOf(ParseResult.Ok::class.java)
@@ -187,7 +193,7 @@ class ParsedArgsTest {
   fun `parses multiple args successfully`() {
     val testResult =
         ParsedArgs.parseOptions(
-            arrayOf("--google-style", "--dry-run", "--set-exit-if-changed", "File.kt"),
+            arrayOf("--style=google", "--dry-run", "--set-exit-if-changed", "File.kt"),
         )
     assertThat(testResult)
         .isEqualTo(
@@ -202,7 +208,7 @@ class ParsedArgsTest {
   @Test
   fun `last style in args wins`() {
     val testResult =
-        ParsedArgs.parseOptions(arrayOf("--google-style", "--kotlinlang-style", "File.kt"))
+        ParsedArgs.parseOptions(arrayOf("--style=google", "--style=kotlinlang", "File.kt"))
     assertThat(testResult)
         .isEqualTo(
             parseResultOk(
@@ -213,7 +219,7 @@ class ParsedArgsTest {
 
   @Test
   fun `error when parsing multiple args and one is unknown`() {
-    val testResult = ParsedArgs.parseOptions(arrayOf("@unknown", "--google-style", "File.kt"))
+    val testResult = ParsedArgs.parseOptions(arrayOf("@unknown", "--style=google", "File.kt"))
     assertThat(testResult).isEqualTo(ParseResult.Error("Unexpected option: @unknown"))
   }