--- a/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/RuntimeSettingsTest.kt
+++ b/mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/RuntimeSettingsTest.kt
@@ -4,27 +4,29 @@
 
 package org.mozilla.geckoview.test
 
 import android.provider.Settings
 import android.support.test.InstrumentationRegistry
 import android.support.test.filters.MediumTest
 import android.support.test.runner.AndroidJUnit4
 import org.hamcrest.Matchers.*
+import org.junit.Ignore
 import org.junit.Test
 import org.junit.runner.RunWith
 import org.mozilla.geckoview.test.rule.GeckoSessionTestRule.ReuseSession
 import org.mozilla.geckoview.test.rule.GeckoSessionTestRule.WithDevToolsAPI
 import kotlin.math.roundToInt
 
 @RunWith(AndroidJUnit4::class)
 @MediumTest
 @ReuseSession(false)
 class RuntimeSettingsTest : BaseSessionTest() {
 
+    @Ignore("disable test for frequently failing Bug 1538430")
     @Test fun automaticFontSize() {
         val settings = sessionRule.runtime.settings
         var initialFontSize = 2.15f
         var initialFontInflation = true
         settings.fontSizeFactor = initialFontSize
         assertThat("initial font scale $initialFontSize set",
                 settings.fontSizeFactor.toDouble(), closeTo(initialFontSize.toDouble(), 0.05))
         settings.fontInflationEnabled = initialFontInflation