diff --git a/gfx/layers/apz/src/APZCTreeManager.cpp b/gfx/layers/apz/src/APZCTreeManager.cpp
index 9c0572efb904..9cf18ea1ba63 100644
--- a/gfx/layers/apz/src/APZCTreeManager.cpp
+++ b/gfx/layers/apz/src/APZCTreeManager.cpp
@@ -22,6 +22,7 @@
 #include "nsThreadUtils.h"              // for NS_IsMainThread
 #include "mozilla/gfx/Logging.h"        // for gfx::TreeLog
 #include "UnitTransforms.h"             // for ViewAs
+#include "gfxPrefs.h"                   // for gfxPrefs
 
 #include <algorithm>                    // for std::stable_sort
 
@@ -127,9 +128,11 @@ APZCTreeManager::UpdatePanZoomControllerTree(CompositorParent* aCompositor,
   // For testing purposes, we log some data to the APZTestData associated with
   // the layers id that originated this update.
   APZTestData* testData = nullptr;
-  if (CompositorParent::LayerTreeState* state = CompositorParent::GetIndirectShadowTree(aOriginatingLayersId)) {
-    testData = &state->mApzTestData;
-    testData->StartNewPaint(aPaintSequenceNumber);
+  if (gfxPrefs::APZTestLoggingEnabled()) {
+    if (CompositorParent::LayerTreeState* state = CompositorParent::GetIndirectShadowTree(aOriginatingLayersId)) {
+      testData = &state->mApzTestData;
+      testData->StartNewPaint(aPaintSequenceNumber);
+    }
   }
   APZPaintLogHelper paintLogger(testData, aPaintSequenceNumber);
 
diff --git a/gfx/layers/apz/src/AsyncPanZoomController.cpp b/gfx/layers/apz/src/AsyncPanZoomController.cpp
index 4b1e71e4a0be..f75eb887fe59 100644
--- a/gfx/layers/apz/src/AsyncPanZoomController.cpp
+++ b/gfx/layers/apz/src/AsyncPanZoomController.cpp
@@ -228,6 +228,9 @@ typedef GeckoContentController::APZStateChange APZStateChange;
  * Maximum amount of time while panning before sending a viewport change. This
  * will asynchronously repaint the page. It is also forced when panning stops.
  *
+ * "apz.test.logging_enabled"
+ * Enable logging of APZ test data (see bug 961289).
+ *
  * "apz.touch_start_tolerance"
  * Constant describing the tolerance in distance we use, multiplied by the
  * device DPI, before we start panning the screen. This is to prevent us from
diff --git a/gfx/layers/client/ClientLayerManager.h b/gfx/layers/client/ClientLayerManager.h
index 9b541f3ea1c7..958a59407da8 100644
--- a/gfx/layers/client/ClientLayerManager.h
+++ b/gfx/layers/client/ClientLayerManager.h
@@ -190,6 +190,9 @@ public:
   {
     mApzTestData.StartNewRepaintRequest(aSequenceNumber);
   }
+  // TODO(botond): When we start using this and write a wrapper similar to
+  // nsLayoutUtils::LogTestDataForPaint(), make sure that wrapper checks
+  // gfxPrefs::APZTestLoggingEnabled().
   void LogTestDataForRepaintRequest(SequenceNumber aSequenceNumber,
                                     FrameMetrics::ViewID aScrollId,
                                     const std::string& aKey,
diff --git a/gfx/thebes/gfxPrefs.h b/gfx/thebes/gfxPrefs.h
index f80aec2942e1..9fc20f09b545 100644
--- a/gfx/thebes/gfxPrefs.h
+++ b/gfx/thebes/gfxPrefs.h
@@ -126,6 +126,7 @@ private:
   DECL_GFX_PREF(Live, "apz.overscroll.snap_back_init_vel",     APZSnapBackInitialVelocity, float, 1.0f);
   DECL_GFX_PREF(Live, "apz.pan_repaint_interval",              APZPanRepaintInterval, int32_t, 250);
   DECL_GFX_PREF(Live, "apz.subframe.enabled",                  APZSubframeEnabled, bool, false);
+  DECL_GFX_PREF(Once, "apz.test.logging_enabled",              APZTestLoggingEnabled, bool, false);
   DECL_GFX_PREF(Live, "apz.touch_start_tolerance",             APZTouchStartTolerance, float, 1.0f/4.5f);
   DECL_GFX_PREF(Live, "apz.use_paint_duration",                APZUsePaintDuration, bool, true);
   DECL_GFX_PREF(Live, "apz.velocity_bias",                     APZVelocityBias, float, 1.0f);
diff --git a/layout/base/nsLayoutUtils.cpp b/layout/base/nsLayoutUtils.cpp
index 70a5e3edd2d7..2a248e6e5954 100644
--- a/layout/base/nsLayoutUtils.cpp
+++ b/layout/base/nsLayoutUtils.cpp
@@ -6577,10 +6577,10 @@ nsLayoutUtils::WantSubAPZC()
 }
 
 /* static */ void
-nsLayoutUtils::LogTestDataForPaint(nsIPresShell* aPresShell,
-                                   ViewID aScrollId,
-                                   const std::string& aKey,
-                                   const std::string& aValue)
+nsLayoutUtils::DoLogTestDataForPaint(nsIPresShell* aPresShell,
+                                     ViewID aScrollId,
+                                     const std::string& aKey,
+                                     const std::string& aValue)
 {
   nsRefPtr<LayerManager> lm = aPresShell->GetPresContext()->GetRootPresContext()
       ->GetPresShell()->GetLayerManager();
diff --git a/layout/base/nsLayoutUtils.h b/layout/base/nsLayoutUtils.h
index 670d2f7a1b0e..b4534ccaf88d 100644
--- a/layout/base/nsLayoutUtils.h
+++ b/layout/base/nsLayoutUtils.h
@@ -27,6 +27,7 @@
 #include "mozilla/gfx/2D.h"
 #include "Units.h"
 #include "mozilla/ToString.h"
+#include "gfxPrefs.h"
 
 #include <limits>
 #include <algorithm>
@@ -2184,7 +2185,11 @@ public:
   static void LogTestDataForPaint(nsIPresShell* aPresShell,
                                   ViewID aScrollId,
                                   const std::string& aKey,
-                                  const std::string& aValue);
+                                  const std::string& aValue) {
+    if (gfxPrefs::APZTestLoggingEnabled()) {
+      DoLogTestDataForPaint(aPresShell, aScrollId, aKey, aValue);
+    }
+  }
 
   /**
    * A convenience overload of LogTestDataForPaint() that accepts any type
@@ -2196,8 +2201,10 @@ public:
                                   ViewID aScrollId,
                                   const std::string& aKey,
                                   const Value& aValue) {
-    LogTestDataForPaint(aPresShell, aScrollId, aKey,
-        mozilla::ToString(aValue));
+    if (gfxPrefs::APZTestLoggingEnabled()) {
+      DoLogTestDataForPaint(aPresShell, aScrollId, aKey,
+          mozilla::ToString(aValue));
+    }
   }
 
  /**
@@ -2231,6 +2238,14 @@ private:
   static bool sInvalidationDebuggingIsEnabled;
   static bool sCSSVariablesEnabled;
   static bool sInterruptibleReflowEnabled;
+
+  /**
+   * Helper function for LogTestDataForPaint().
+   */
+  static void DoLogTestDataForPaint(nsIPresShell* aPresShell,
+                                    ViewID aScrollId,
+                                    const std::string& aKey,
+                                    const std::string& aValue);
 };
 
 MOZ_FINISH_NESTED_ENUM_CLASS(nsLayoutUtils::RepaintMode)
diff --git a/modules/libpref/src/init/all.js b/modules/libpref/src/init/all.js
index 7b4b7bf3bb0b..76122ebcbec3 100644
--- a/modules/libpref/src/init/all.js
+++ b/modules/libpref/src/init/all.js
@@ -371,6 +371,9 @@ pref("apz.printtree", false);
 // Layerize scrollable subframes to allow async panning
 pref("apz.subframe.enabled", false);
 
+// APZ testing (bug 961289)
+pref("apz.test.logging_enabled", false);
+
 #ifdef XP_MACOSX
 // Whether to run in native HiDPI mode on machines with "Retina"/HiDPI display;
 //   <= 0 : hidpi mode disabled, display will just use pixel-based upscaling
diff --git a/testing/profiles/prefs_general.js b/testing/profiles/prefs_general.js
index c56052b2ca49..cb97283aaac9 100644
--- a/testing/profiles/prefs_general.js
+++ b/testing/profiles/prefs_general.js
@@ -190,3 +190,6 @@ user_pref('toolkit.telemetry.server', 'https://%(server)s/telemetry-dummy/');
 // actually need a functioning FxA server, so just set it to something that
 // resolves and accepts requests, even if they all fail.
 user_pref('identity.fxaccounts.auth.uri', 'https://%(server)s/fxa-dummy/');
+
+// Enable logging of APZ test data (see bug 961289).
+user_pref('apz.test.logging_enabled', true);