diff --git a/Lib/fontTools/ttLib/ttFont.py b/Lib/fontTools/ttLib/ttFont.py
index 692f99ac8..4adf34af1 100644
--- a/Lib/fontTools/ttLib/ttFont.py
+++ b/Lib/fontTools/ttLib/ttFont.py
@@ -129,7 +129,7 @@ class TTFont(object):
 			closeStream = False
 			file.seek(0)
 
-		if not self.lazy:
+		if self.lazy is None:
 			# read input file in memory and wrap a stream around it to allow overwriting
 			file.seek(0)
 			tmp = BytesIO(file.read())
@@ -139,12 +139,19 @@ class TTFont(object):
 			if closeStream:
 				file.close()
 			file = tmp
+
 		self._tableCache = _tableCache
 		self.reader = SFNTReader(file, checkChecksums, fontNumber=fontNumber)
 		self.sfntVersion = self.reader.sfntVersion
 		self.flavor = self.reader.flavor
 		self.flavorData = self.reader.flavorData
 
+		if self.lazy is False:
+			# if lazy=False immediately load all the tables
+			self.ensureDecompiled()
+			if closeStream:
+				file.close()
+
 	def __enter__(self):
 		return self
 
@@ -378,6 +385,14 @@ class TTFont(object):
 		keys = sortedTagList(keys)
 		return ["GlyphOrder"] + keys
 
+	def ensureDecompiled(self):
+		"""Decompile all the tables, even if a TTFont was opened in 'lazy' mode."""
+		for tag in self.keys():
+			table = self[tag]
+			if self.lazy is not False and hasattr(table, "ensureDecompiled"):
+				table.ensureDecompiled()
+		self.lazy = False
+
 	def __len__(self):
 		return len(list(self.keys()))