diff --git a/app/src/main/java/org/mozilla/fenix/components/Components.kt b/app/src/main/java/org/mozilla/fenix/components/Components.kt
index f6e94701b..24846cc4d 100644
--- a/app/src/main/java/org/mozilla/fenix/components/Components.kt
+++ b/app/src/main/java/org/mozilla/fenix/components/Components.kt
@@ -17,8 +17,10 @@ import mozilla.components.feature.addons.update.DefaultAddonUpdater
 import mozilla.components.lib.publicsuffixlist.PublicSuffixList
 import mozilla.components.support.migration.state.MigrationStore
 import org.mozilla.fenix.BuildConfig
+import org.mozilla.fenix.Config
 import org.mozilla.fenix.HomeActivity
 import org.mozilla.fenix.components.metrics.AppStartupTelemetry
+import org.mozilla.fenix.ext.settings
 import org.mozilla.fenix.utils.ClipboardHandler
 import org.mozilla.fenix.utils.Mockable
 import org.mozilla.fenix.utils.Settings
@@ -71,14 +73,26 @@ class Components(private val context: Context) {
     }
 
     val addonCollectionProvider by lazy {
-        if (!BuildConfig.AMO_COLLECTION.isNullOrEmpty()) {
+        // Check if we have a customized (overridden) AMO collection (only supported in Nightly)
+        if (Config.channel.isNightlyOrDebug && context.settings().amoCollectionOverrideConfigured()) {
+            AddonCollectionProvider(
+                context,
+                core.client,
+                collectionUser = context.settings().overrideAmoUser,
+                collectionName = context.settings().overrideAmoCollection
+            )
+        }
+        // Use build config otherwise
+        else if (!BuildConfig.AMO_COLLECTION.isNullOrEmpty()) {
             AddonCollectionProvider(
                 context,
                 core.client,
                 collectionName = BuildConfig.AMO_COLLECTION,
                 maxCacheAgeInMinutes = DAY_IN_MINUTES
             )
-        } else {
+        }
+        // Fall back to defaults
+        else {
             AddonCollectionProvider(context, core.client, maxCacheAgeInMinutes = DAY_IN_MINUTES)
         }
     }
diff --git a/app/src/main/java/org/mozilla/fenix/settings/SettingsFragment.kt b/app/src/main/java/org/mozilla/fenix/settings/SettingsFragment.kt
index 6f0719487..df29c2916 100644
--- a/app/src/main/java/org/mozilla/fenix/settings/SettingsFragment.kt
+++ b/app/src/main/java/org/mozilla/fenix/settings/SettingsFragment.kt
@@ -6,13 +6,16 @@ package org.mozilla.fenix.settings
 
 import android.annotation.SuppressLint
 import android.content.ActivityNotFoundException
+import android.content.DialogInterface
 import android.content.Intent
 import android.net.Uri
 import android.os.Build
 import android.os.Bundle
 import android.os.Handler
-import android.provider.Settings
+import android.view.LayoutInflater
 import android.widget.Toast
+import androidx.annotation.VisibleForTesting
+import androidx.appcompat.app.AlertDialog
 import androidx.lifecycle.lifecycleScope
 import androidx.navigation.NavDirections
 import androidx.navigation.findNavController
@@ -20,6 +23,8 @@ import androidx.navigation.fragment.navArgs
 import androidx.preference.Preference
 import androidx.preference.PreferenceFragmentCompat
 import androidx.recyclerview.widget.RecyclerView
+import kotlinx.android.synthetic.main.amo_collection_override_dialog.view.*
+import kotlinx.android.synthetic.main.fragment_installed_add_on_details.view.*
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.launch
@@ -28,6 +33,7 @@ import mozilla.components.concept.sync.AuthType
 import mozilla.components.concept.sync.OAuthAccount
 import mozilla.components.concept.sync.Profile
 import mozilla.components.support.ktx.android.content.getColorFromAttr
+import mozilla.components.support.ktx.android.view.showKeyboard
 import org.mozilla.fenix.BrowserDirection
 import org.mozilla.fenix.Config
 import org.mozilla.fenix.FeatureFlags
@@ -43,6 +49,7 @@ import org.mozilla.fenix.ext.requireComponents
 import org.mozilla.fenix.ext.settings
 import org.mozilla.fenix.ext.showToolbar
 import org.mozilla.fenix.settings.account.AccountUiView
+import org.mozilla.fenix.utils.Settings
 import kotlin.system.exitProcess
 
 @Suppress("LargeClass", "TooManyFunctions")
@@ -304,6 +311,41 @@ class SettingsFragment : PreferenceFragmentCompat() {
             resources.getString(R.string.pref_key_debug_settings) -> {
                 SettingsFragmentDirections.actionSettingsFragmentToSecretSettingsFragment()
             }
+            resources.getString(R.string.pref_key_override_amo_collection) -> {
+                val context = requireContext()
+                val dialogView = LayoutInflater.from(context).inflate(R.layout.amo_collection_override_dialog, null)
+
+                AlertDialog.Builder(context).apply {
+                    setTitle(context.getString(R.string.preferences_customize_amo_collection))
+                    setView(dialogView)
+                    setNegativeButton(R.string.customize_addon_collection_cancel) { dialog: DialogInterface, _ ->
+                        dialog.cancel()
+                    }
+
+                    setPositiveButton(R.string.customize_addon_collection_ok) { _, _ ->
+                        context.settings().overrideAmoUser = dialogView.custom_amo_user.text.toString()
+                        context.settings().overrideAmoCollection = dialogView.custom_amo_collection.text.toString()
+
+                        Toast.makeText(
+                            context,
+                            getString(R.string.toast_customize_addon_collection_done),
+                            Toast.LENGTH_LONG
+                        ).show()
+
+                        Handler().postDelayed({
+                            exitProcess(0)
+                        }, AMO_COLLECTION_OVERRIDE_EXIT_DELAY)
+                    }
+
+                    dialogView.custom_amo_collection.setText(context.settings().overrideAmoCollection)
+                    dialogView.custom_amo_user.setText(context.settings().overrideAmoUser)
+                    dialogView.custom_amo_user.requestFocus()
+                    dialogView.custom_amo_user.showKeyboard()
+                    create()
+                }.show()
+
+                null
+            }
             else -> null
         }
         directions?.let { navigateFromSettings(directions) }
@@ -374,12 +416,14 @@ class SettingsFragment : PreferenceFragmentCompat() {
         findPreference<Preference>(
             getPreferenceKey(R.string.pref_key_debug_settings)
         )?.isVisible = requireContext().settings().showSecretDebugMenuThisSession
+
+        setupAmoCollectionOverridePreference(requireContext().settings())
     }
 
     private fun getClickListenerForMakeDefaultBrowser(): Preference.OnPreferenceClickListener {
         return if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
             Preference.OnPreferenceClickListener {
-                val intent = Intent(Settings.ACTION_MANAGE_DEFAULT_APPS_SETTINGS)
+                val intent = Intent(android.provider.Settings.ACTION_MANAGE_DEFAULT_APPS_SETTINGS)
                 startActivity(intent)
                 true
             }
@@ -446,8 +490,23 @@ class SettingsFragment : PreferenceFragmentCompat() {
         }
     }
 
+    @VisibleForTesting
+    internal fun setupAmoCollectionOverridePreference(settings: Settings) {
+        val preferenceAmoCollectionOverride =
+            findPreference<Preference>(getPreferenceKey(R.string.pref_key_override_amo_collection))
+
+        val show = (Config.channel.isNightlyOrDebug && (
+            settings.amoCollectionOverrideConfigured() || settings.showSecretDebugMenuThisSession)
+        )
+        preferenceAmoCollectionOverride?.apply {
+            isVisible = show
+            summary = settings.overrideAmoCollection.ifEmpty { null }
+        }
+    }
+
     companion object {
         private const val SCROLL_INDICATOR_DELAY = 10L
         private const val FXA_SYNC_OVERRIDE_EXIT_DELAY = 2000L
+        private const val AMO_COLLECTION_OVERRIDE_EXIT_DELAY = 3000L
     }
 }
diff --git a/app/src/main/java/org/mozilla/fenix/utils/Settings.kt b/app/src/main/java/org/mozilla/fenix/utils/Settings.kt
index a0bd0ad76..16f07e438 100644
--- a/app/src/main/java/org/mozilla/fenix/utils/Settings.kt
+++ b/app/src/main/java/org/mozilla/fenix/utils/Settings.kt
@@ -886,6 +886,20 @@ class Settings(private val appContext: Context) : PreferencesHolder {
         default = ""
     )
 
+    var overrideAmoUser by stringPreference(
+        appContext.getPreferenceKey(R.string.pref_key_override_amo_user),
+        default = ""
+    )
+
+    var overrideAmoCollection by stringPreference(
+        appContext.getPreferenceKey(R.string.pref_key_override_amo_collection),
+        default = ""
+    )
+
+    fun amoCollectionOverrideConfigured(): Boolean {
+        return overrideAmoUser.isNotEmpty() || overrideAmoCollection.isNotEmpty()
+    }
+
     val topSitesSize by intPreference(
         appContext.getPreferenceKey(R.string.pref_key_top_sites_size),
         default = 0
diff --git a/app/src/main/res/layout/amo_collection_override_dialog.xml b/app/src/main/res/layout/amo_collection_override_dialog.xml
new file mode 100644
index 000000000..b913795b4
--- /dev/null
+++ b/app/src/main/res/layout/amo_collection_override_dialog.xml
@@ -0,0 +1,32 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+        android:id="@+id/linear_layout"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:orientation="vertical">
+
+    <EditText
+        android:id="@+id/custom_amo_user"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:hint="@string/customize_addon_collection_user_hint"
+        android:singleLine="true"
+        android:layout_marginStart="16dp"
+        android:layout_marginEnd="16dp"
+        android:layout_marginTop="8dp"
+        android:textColor="?primaryText"/>
+
+    <EditText
+        android:id="@+id/custom_amo_collection"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:hint="@string/customize_addon_collection_hint"
+        android:singleLine="true"
+        android:layout_marginStart="16dp"
+        android:layout_marginEnd="16dp"
+        android:textColor="?primaryText"/>
+
+</LinearLayout>
diff --git a/app/src/main/res/values/preference_keys.xml b/app/src/main/res/values/preference_keys.xml
index 63673a9b5..d455228fe 100644
--- a/app/src/main/res/values/preference_keys.xml
+++ b/app/src/main/res/values/preference_keys.xml
@@ -35,6 +35,8 @@
     <string name="pref_key_delete_browsing_data_on_quit_categories" translatable="false">pref_key_delete_browsing_data_on_quit_categories</string>
     <string name="pref_key_last_known_mode_private" translatable="false">pref_key_last_known_mode_private</string>
     <string name="pref_key_addons" translatable="false">pref_key_addons</string>
+    <string name="pref_key_override_amo_user" translatable="false">pref_key_override_amo_user</string>
+    <string name="pref_key_override_amo_collection" translatable="false">pref_key_override_amo_collection</string>
     <string name="pref_key_last_maintenance" translatable="false">pref_key_last_maintenance</string>
     <string name="pref_key_help" translatable="false">pref_key_help</string>
     <string name="pref_key_rate" translatable="false">pref_key_rate</string>
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 4a9e2c55b..1465e3623 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -337,6 +337,20 @@
     <!-- Preference for notifications -->
     <string name="preferences_notifications">Notifications</string>
 
+    <!-- Add-on Preferences -->
+    <!-- Preference to customize the configured AMO (addons.mozilla.org) collection -->
+    <string name="preferences_customize_amo_collection">Custom Add-on collection</string>
+    <!-- Button caption to confirm the add-on collection configuration -->
+    <string name="customize_addon_collection_ok">OK</string>
+    <!-- Button caption to abort the add-on collection configuration -->
+    <string name="customize_addon_collection_cancel">Cancel</string>
+    <!-- Hint displayed on input field for custom collection name -->
+    <string name="customize_addon_collection_hint">Collection name</string>
+    <!-- Hint displayed on input field for custom collection user ID-->
+    <string name="customize_addon_collection_user_hint">Collection owner (User ID)</string>
+    <!-- Toast shown after confirming the custom add-on collection configuration -->
+    <string name="toast_customize_addon_collection_done">Add-on collection modified. Quitting the application to apply changes…</string>
+
     <!-- Account Preferences -->
     <!-- Preference for triggering sync -->
     <string name="preferences_sync_now">Sync now</string>
diff --git a/app/src/main/res/xml/preferences.xml b/app/src/main/res/xml/preferences.xml
index e1f18cd8c..9fcdcf316 100644
--- a/app/src/main/res/xml/preferences.xml
+++ b/app/src/main/res/xml/preferences.xml
@@ -136,6 +136,11 @@
             android:key="@string/pref_key_addons"
             android:title="@string/preferences_addons" />
 
+        <androidx.preference.Preference
+            android:icon="@drawable/ic_addons_extensions"
+            android:key="@string/pref_key_override_amo_collection"
+            android:title="@string/preferences_customize_amo_collection"/>
+
         <androidx.preference.SwitchPreference
             android:defaultValue="false"
             android:icon="@drawable/ic_open_in_app"
diff --git a/app/src/test/java/org/mozilla/fenix/settings/SettingsFragmentTest.kt b/app/src/test/java/org/mozilla/fenix/settings/SettingsFragmentTest.kt
new file mode 100644
index 000000000..8a6d2ad64
--- /dev/null
+++ b/app/src/test/java/org/mozilla/fenix/settings/SettingsFragmentTest.kt
@@ -0,0 +1,76 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.fenix.settings
+
+import androidx.fragment.app.FragmentActivity
+import androidx.preference.Preference
+import io.mockk.every
+import io.mockk.mockk
+import org.junit.Assert.assertFalse
+import org.junit.Assert.assertNotNull
+import org.junit.Assert.assertTrue
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.mozilla.fenix.R
+import org.mozilla.fenix.ext.getPreferenceKey
+import org.mozilla.fenix.helpers.FenixRobolectricTestRunner
+import org.mozilla.fenix.utils.Settings
+import org.robolectric.Robolectric
+
+@RunWith(FenixRobolectricTestRunner::class)
+class SettingsFragmentTest {
+
+    @Test
+    fun `Add-on collection override pref is visible if debug menu active`() {
+        val settingsFragment = SettingsFragment()
+        val activity = Robolectric.buildActivity(FragmentActivity::class.java).create().get()
+
+        activity.supportFragmentManager.beginTransaction()
+            .add(settingsFragment, "test")
+            .commitNow()
+
+        val preferenceAmoCollectionOverride = settingsFragment.findPreference<Preference>(
+            settingsFragment.getPreferenceKey(R.string.pref_key_override_amo_collection)
+        )
+
+        settingsFragment.setupAmoCollectionOverridePreference(mockk(relaxed = true))
+        assertNotNull(preferenceAmoCollectionOverride)
+        assertFalse(preferenceAmoCollectionOverride!!.isVisible)
+
+        val settings: Settings = mockk(relaxed = true)
+        every { settings.showSecretDebugMenuThisSession } returns true
+        settingsFragment.setupAmoCollectionOverridePreference(settings)
+        assertTrue(preferenceAmoCollectionOverride.isVisible)
+    }
+
+    @Test
+    fun `Add-on collection override pref is visible if already configured`() {
+        val settingsFragment = SettingsFragment()
+        val activity = Robolectric.buildActivity(FragmentActivity::class.java).create().get()
+
+        activity.supportFragmentManager.beginTransaction()
+            .add(settingsFragment, "test")
+            .commitNow()
+
+        val preferenceAmoCollectionOverride = settingsFragment.findPreference<Preference>(
+            settingsFragment.getPreferenceKey(R.string.pref_key_override_amo_collection)
+        )
+
+        settingsFragment.setupAmoCollectionOverridePreference(mockk(relaxed = true))
+        assertNotNull(preferenceAmoCollectionOverride)
+        assertFalse(preferenceAmoCollectionOverride!!.isVisible)
+
+        val settings: Settings = mockk(relaxed = true)
+        every { settings.showSecretDebugMenuThisSession } returns false
+
+        every { settings.amoCollectionOverrideConfigured() } returns false
+        settingsFragment.setupAmoCollectionOverridePreference(settings)
+        assertFalse(preferenceAmoCollectionOverride.isVisible)
+
+        every { settings.amoCollectionOverrideConfigured() } returns true
+        settingsFragment.setupAmoCollectionOverridePreference(settings)
+        assertTrue(preferenceAmoCollectionOverride.isVisible)
+    }
+}
diff --git a/app/src/test/java/org/mozilla/fenix/utils/SettingsTest.kt b/app/src/test/java/org/mozilla/fenix/utils/SettingsTest.kt
index 456b946e8..4ff101244 100644
--- a/app/src/test/java/org/mozilla/fenix/utils/SettingsTest.kt
+++ b/app/src/test/java/org/mozilla/fenix/utils/SettingsTest.kt
@@ -576,4 +576,34 @@ class SettingsTest {
             settings.getSitePermissionsCustomSettingsRules()
         )
     }
+
+    @Test
+    fun overrideAmoCollection() {
+        // When just created
+        // Then
+        assertEquals("", settings.overrideAmoCollection)
+        assertFalse(settings.amoCollectionOverrideConfigured())
+
+        // When
+        settings.overrideAmoCollection = "testCollection"
+
+        // Then
+        assertEquals("testCollection", settings.overrideAmoCollection)
+        assertTrue(settings.amoCollectionOverrideConfigured())
+    }
+
+    @Test
+    fun overrideAmoUser() {
+        // When just created
+        // Then
+        assertEquals("", settings.overrideAmoUser)
+        assertFalse(settings.amoCollectionOverrideConfigured())
+
+        // When
+        settings.overrideAmoUser = "testAmoUser"
+
+        // Then
+        assertEquals("testAmoUser", settings.overrideAmoUser)
+        assertTrue(settings.amoCollectionOverrideConfigured())
+    }
 }