diff --git a/font-src/otl/index.ptl b/font-src/otl/index.ptl
index a4a399741..fd90c02d5 100644
--- a/font-src/otl/index.ptl
+++ b/font-src/otl/index.ptl
@@ -1,5 +1,4 @@
 import 'toposort' as toposort
-import 'object-assign' as objectAssign
 import '../support/glyph' as Glyph
 import '../support/transform' as Transform
 
@@ -34,7 +33,7 @@ define [buildGSUB para glyphStore markGlyphs] : begin
 
 	# Ligation
 	if para.enableLigation : do
-		define plm : objectAssign {.} para.ligation.defaultBuildup
+		define plm : Object.assign {.} para.ligation.defaultBuildup
 		if (para.ligation.caltBuildup && para.ligation.caltBuildup.length) : begin
 			set plm.calt para.ligation.caltBuildup
 		buildLigations gsub para plm
diff --git a/package.json b/package.json
index 26094ed02..cbd6f954d 100644
--- a/package.json
+++ b/package.json
@@ -13,7 +13,6 @@
     "cldr": "^5.8.0",
     "ejs": "^3.1.5",
     "fs-extra": "^9.0.1",
-    "object-assign": "^4.1.1",
     "ot-builder": "^1.0.0",
     "otb-ttc-bundle": "^1.0.0",
     "patel": "^0.34.0",