diff --git a/dom/base/nsJSEnvironment.cpp b/dom/base/nsJSEnvironment.cpp
index 2d47abbe23..5acc9ed692 100644
--- a/dom/base/nsJSEnvironment.cpp
+++ b/dom/base/nsJSEnvironment.cpp
@@ -2337,6 +2337,7 @@ SetMemoryGCModePrefChangedCallback(const char* aPrefName, void* aClosure)
 {
   bool enableCompartmentGC = Preferences::GetBool("javascript.options.mem.gc_per_compartment");
   bool enableIncrementalGC = Preferences::GetBool("javascript.options.mem.gc_incremental");
+  bool enableGenerationalGC = Preferences::GetBool("javascript.options.mem.gc_generational");
   JSGCMode mode;
   if (enableIncrementalGC) {
     mode = JSGC_MODE_INCREMENTAL;
@@ -2346,6 +2347,7 @@ SetMemoryGCModePrefChangedCallback(const char* aPrefName, void* aClosure)
     mode = JSGC_MODE_GLOBAL;
   }
   JS_SetGCParameter(sRuntime, JSGC_MODE, mode);
+  JS_SetGGCMode(sRuntime, enableGenerationalGC);
 }
 
 static void
@@ -2626,6 +2628,9 @@ nsJSContext::EnsureStatics()
   Preferences::RegisterCallbackAndCall(SetMemoryGCSliceTimePrefChangedCallback,
                                        "javascript.options.mem.gc_incremental_slice_ms");
 
+  Preferences::RegisterCallbackAndCall(SetMemoryGCModePrefChangedCallback,
+                                       "javascript.options.mem.gc_generational");
+
   Preferences::RegisterCallbackAndCall(SetMemoryGCCompactingPrefChangedCallback,
                                        "javascript.options.mem.gc_compacting");
 
diff --git a/js/src/jsapi.cpp b/js/src/jsapi.cpp
index de936fb712..1be04890b5 100644
--- a/js/src/jsapi.cpp
+++ b/js/src/jsapi.cpp
@@ -1393,6 +1393,18 @@ JS_SetGCParameter(JSRuntime* rt, JSGCParamKey key, uint32_t value)
     rt->gc.setParameter(key, value);
 }
 
+JS_PUBLIC_API(void)
+JS_SetGGCMode(JSRuntime* rt, bool enabled)
+{
+  // Control GGC
+  if (enabled && !rt->gc.isGenerationalGCEnabled()) {
+    rt->gc.enableGenerationalGC();
+  } else if (!enabled && rt->gc.isGenerationalGCEnabled()) {
+    rt->gc.disableGenerationalGC();
+  }
+}
+
+
 JS_PUBLIC_API(uint32_t)
 JS_GetGCParameter(JSRuntime* rt, JSGCParamKey key)
 {
diff --git a/js/src/jsapi.h b/js/src/jsapi.h
index 9b641c2ad4..733d890281 100644
--- a/js/src/jsapi.h
+++ b/js/src/jsapi.h
@@ -1850,6 +1850,9 @@ typedef enum JSGCParamKey {
 extern JS_PUBLIC_API(void)
 JS_SetGCParameter(JSRuntime* rt, JSGCParamKey key, uint32_t value);
 
+extern JS_PUBLIC_API(void)
+JS_SetGGCMode(JSRuntime* rt, bool enabled);
+
 extern JS_PUBLIC_API(uint32_t)
 JS_GetGCParameter(JSRuntime* rt, JSGCParamKey key);
 
diff --git a/modules/libpref/init/all.js b/modules/libpref/init/all.js
index fd518b3f58..ef539eef4b 100644
--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -1058,6 +1058,7 @@ pref("javascript.options.mem.max", -1);
 pref("javascript.options.mem.gc_per_compartment", true);
 pref("javascript.options.mem.gc_incremental", true);
 pref("javascript.options.mem.gc_incremental_slice_ms", 20);
+pref("javascript.options.mem.gc_generational", false);
 pref("javascript.options.mem.gc_compacting", true);
 pref("javascript.options.mem.log", false);
 pref("javascript.options.mem.notify", false);