diff --git a/js/public/MemoryMetrics.h b/js/public/MemoryMetrics.h
index 2a5d4517e38..fb74b260b31 100644
--- a/js/public/MemoryMetrics.h
+++ b/js/public/MemoryMetrics.h
@@ -214,6 +214,7 @@ struct GCSizes
 {
 #define FOR_EACH_SIZE(macro) \
     macro(_, _, marker) \
+    macro(_, _, nursery) \
     macro(_, _, storeBufferVals) \
     macro(_, _, storeBufferCells) \
     macro(_, _, storeBufferSlots) \
diff --git a/js/src/gc/Nursery.h b/js/src/gc/Nursery.h
index 524ba30c1fc..9f0310abb83 100644
--- a/js/src/gc/Nursery.h
+++ b/js/src/gc/Nursery.h
@@ -123,6 +123,8 @@ class Nursery
     /* Forward a slots/elements pointer stored in an Ion frame. */
     void forwardBufferPointer(HeapSlot **pSlotsElems);
 
+    size_t sizeOfHeap() { return start() ? NurserySize : 0; }
+
 #ifdef JS_GC_ZEAL
     /*
      * In debug and zeal builds, these bytes indicate the state of an unused
diff --git a/js/src/vm/Runtime.cpp b/js/src/vm/Runtime.cpp
index c1613837768..57ce574e3a7 100644
--- a/js/src/vm/Runtime.cpp
+++ b/js/src/vm/Runtime.cpp
@@ -624,6 +624,7 @@ JSRuntime::addSizeOfIncludingThis(mozilla::MallocSizeOf mallocSizeOf, JS::Runtim
 
     rtSizes->gc.marker += gcMarker.sizeOfExcludingThis(mallocSizeOf);
 #ifdef JSGC_GENERATIONAL
+    rtSizes->gc.nursery += gcNursery.sizeOfHeap();
     gcStoreBuffer.addSizeOfExcludingThis(mallocSizeOf, &rtSizes->gc);
 #endif
 }
diff --git a/js/xpconnect/src/XPCJSRuntime.cpp b/js/xpconnect/src/XPCJSRuntime.cpp
index 31207c994a7..775b958f65d 100644
--- a/js/xpconnect/src/XPCJSRuntime.cpp
+++ b/js/xpconnect/src/XPCJSRuntime.cpp
@@ -2308,6 +2308,10 @@ ReportJSRuntimeExplicitTreeStats(const JS::RuntimeStats &rtStats,
                   KIND_HEAP, rtStats.runtime.gc.marker,
                   "Memory used for the GC mark stack and gray roots.");
 
+    RREPORT_BYTES(rtPath + NS_LITERAL_CSTRING("runtime/gc/nursery"),
+                  KIND_NONHEAP, rtStats.runtime.gc.nursery,
+                  "Memory used for the GC nursery.");
+
     RREPORT_BYTES(rtPath + NS_LITERAL_CSTRING("runtime/gc/store-buffer/vals"),
                   KIND_HEAP, rtStats.runtime.gc.storeBufferVals,
                   "Memory used for values in the store buffer.");