diff --git a/config/external/fdlibm/moz.build b/config/external/fdlibm/moz.build
new file mode 100644
index 000000000000..f7f246568917
--- /dev/null
+++ b/config/external/fdlibm/moz.build
@@ -0,0 +1,14 @@
+# -*- Mode: python; c-basic-offset: 4; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# 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/.
+
+Library('fdlibm')
+
+with Files('**'):
+    BUG_COMPONENT = ('Core', 'JavaScript Engine')
+
+DIRS += [
+    '../../../modules/fdlibm',
+]
diff --git a/modules/fdlibm/moz.build b/modules/fdlibm/moz.build
new file mode 100644
index 000000000000..ca27d19959d5
--- /dev/null
+++ b/modules/fdlibm/moz.build
@@ -0,0 +1,7 @@
+# -*- Mode: python; c-basic-offset: 4; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# 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/.
+
+DIRS += ['src']
diff --git a/modules/fdlibm/src/moz.build b/modules/fdlibm/src/moz.build
new file mode 100644
index 000000000000..78a41ecf7482
--- /dev/null
+++ b/modules/fdlibm/src/moz.build
@@ -0,0 +1,71 @@
+# -*- Mode: python; c-basic-offset: 4; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# 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/.
+
+EXPORTS += [
+    'fdlibm.h',
+]
+
+FINAL_LIBRARY = 'fdlibm'
+
+if CONFIG['GNU_CXX']:
+    CXXFLAGS += [
+        '-Wno-parentheses',
+        '-Wno-sign-compare',
+    ]
+
+if CONFIG['CLANG_CXX']:
+    CXXFLAGS += [
+        '-Wno-dangling-else',
+    ]
+
+if CONFIG['_MSC_VER']:
+    CXXFLAGS += [
+        '-wd4018', # signed/unsigned mismatch
+        '-wd4146', # unary minus operator applied to unsigned type
+        '-wd4305', # truncation from 'double' to 'const float'
+        '-wd4723', # potential divide by 0
+        '-wd4756', # overflow in constant arithmetic
+    ]
+
+SOURCES += [
+    'e_acos.cpp',
+    'e_acosh.cpp',
+    'e_asin.cpp',
+    'e_atan2.cpp',
+    'e_atanh.cpp',
+    'e_cosh.cpp',
+    'e_exp.cpp',
+    'e_hypot.cpp',
+    'e_log.cpp',
+    'e_log10.cpp',
+    'e_log2.cpp',
+    'e_pow.cpp',
+    'e_rem_pio2.cpp',
+    'e_sinh.cpp',
+    'e_sqrt.cpp',
+    'k_cos.cpp',
+    'k_exp.cpp',
+    'k_rem_pio2.cpp',
+    'k_sin.cpp',
+    'k_tan.cpp',
+    's_asinh.cpp',
+    's_atan.cpp',
+    's_cbrt.cpp',
+    's_ceil.cpp',
+    's_ceilf.cpp',
+    's_copysign.cpp',
+    's_cos.cpp',
+    's_expm1.cpp',
+    's_fabs.cpp',
+    's_floor.cpp',
+    's_floorf.cpp',
+    's_log1p.cpp',
+    's_scalbn.cpp',
+    's_sin.cpp',
+    's_tan.cpp',
+    's_tanh.cpp',
+    's_trunc.cpp',
+]
diff --git a/moz.build b/moz.build
index 3f648874cad1..2964d5e60077 100644
--- a/moz.build
+++ b/moz.build
@@ -51,6 +51,7 @@ if not CONFIG['JS_STANDALONE']:
     ]
 
 DIRS += [
+    'config/external/fdlibm',
     'config/external/zlib',
     'memory',
     'mfbt',