diff --git a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/InputMethods.java b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/InputMethods.java
index 51728c081add..8015fa21a5e7 100644
--- a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/InputMethods.java
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/InputMethods.java
@@ -16,8 +16,11 @@ import android.view.inputmethod.InputMethodManager;
 
 final public class InputMethods {
     public static final String METHOD_ANDROID_LATINIME = "com.android.inputmethod.latin/.LatinIME";
-    public static final String METHOD_ATOK = "com.justsystems.atokmobile.service/.AtokInputMethodService";
+    // ATOK has a lot of package names since they release custom versions.
+    public static final String METHOD_ATOK_PREFIX = "com.justsystems.atokmobile.";
+    public static final String METHOD_ATOK_OEM_PREFIX = "com.atok.mobile.";
     public static final String METHOD_GOOGLE_JAPANESE_INPUT = "com.google.android.inputmethod.japanese/.MozcService";
+    public static final String METHOD_ATOK_OEM_SOFTBANK = "com.mobiroo.n.justsystems.atok/.AtokInputMethodService";
     public static final String METHOD_GOOGLE_LATINIME = "com.google.android.inputmethod.latin/com.android.inputmethod.latin.LatinIME";
     public static final String METHOD_HTC_TOUCH_INPUT = "com.htc.android.htcime/.HTCIMEService";
     public static final String METHOD_IWNN = "jp.co.omronsoft.iwnnime.ml/.standardcommon.IWnnLanguageSwitcher";
@@ -59,14 +62,29 @@ final public class InputMethods {
         }
     }
 
-    public static boolean needsSoftResetWorkaround(String inputMethod) {
+    public static boolean needsSoftResetWorkaround(final String inputMethod) {
         // Stock latin IME on Android 4.2 and above
         return Build.VERSION.SDK_INT >= 17 &&
                (METHOD_ANDROID_LATINIME.equals(inputMethod) ||
                 METHOD_GOOGLE_LATINIME.equals(inputMethod));
     }
 
-    public static boolean shouldCommitCharAsKey(String inputMethod) {
+    /**
+     * Check input method if we require a workaround to remove composition in
+     * {@link android.view.inputmethod.InputMethodManager.updateSelection}.
+     *
+     * @param inputMethod The input method name by {@link #getCurrentInputMethod}.
+     * @return true if {@link android.view.inputmethod.InputMethodManager.updateSelection}
+     * doesn't remove the composition, use {@link android.view.inputmethod.InputMehtodManager.restartInput}
+     * to remove it in this case.
+     */
+    public static boolean needsRestartInput(final String inputMethod) {
+        return inputMethod.startsWith(METHOD_ATOK_PREFIX) ||
+               inputMethod.startsWith(METHOD_ATOK_OEM_PREFIX) ||
+               METHOD_ATOK_OEM_SOFTBANK.equals(inputMethod);
+    }
+
+    public static boolean shouldCommitCharAsKey(final String inputMethod) {
         return METHOD_HTC_TOUCH_INPUT.equals(inputMethod);
     }
 
diff --git a/mobile/android/geckoview/src/main/java/org/mozilla/geckoview/SessionTextInput.java b/mobile/android/geckoview/src/main/java/org/mozilla/geckoview/SessionTextInput.java
index 74b723d696d3..b37c7ae28869 100644
--- a/mobile/android/geckoview/src/main/java/org/mozilla/geckoview/SessionTextInput.java
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/geckoview/SessionTextInput.java
@@ -205,6 +205,19 @@ public final class SessionTextInput {
             final View view = session.getTextInput().getView();
             final InputMethodManager imm = getInputMethodManager(view);
             if (imm != null) {
+                // When composition start and end is -1,
+                // InputMethodManager.updateSelection will remove composition
+                // on most IMEs. But ATOK series do nothing. So we have to
+                // restart input method to remove composition as workaround.
+                if (compositionStart < 0 && compositionEnd < 0 &&
+                    InputMethods.needsRestartInput(
+                        InputMethods.getCurrentInputMethod(view.getContext()))) {
+                    try {
+                        imm.restartInput(view);
+                    } catch (RuntimeException e) {
+                        Log.e(LOGTAG, "Error restarting input", e);
+                    }
+                }
                 imm.updateSelection(view, selStart, selEnd, compositionStart, compositionEnd);
             }
         }