diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4905a16f0..c9b0c0604 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,7 @@
 
 ### Improvements
 
+- Change to disable the smart quotes option in the Mode settings by default.
 - Draw invisible symbols for invisible operators (U+2061, U+2062, U+2063, and U+2064).
 - Update the Lisp, Lua, Scheme, and Tcl syntaxes to update interpreters (thanks to Renfei!).
 - [non-AppStore ver.] Update Sparkle from 2.6.3 to 2.6.4.
diff --git a/CotEditor/Sources/ModeOptions.swift b/CotEditor/Sources/ModeOptions.swift
index e3c8b164d..72fc131c6 100644
--- a/CotEditor/Sources/ModeOptions.swift
+++ b/CotEditor/Sources/ModeOptions.swift
@@ -62,7 +62,7 @@ extension Syntax.Kind {
                 ModeOptions(
                     fontType: .standard,
                     smartInsertDelete: true,
-                    automaticQuoteSubstitution: true,
+                    automaticQuoteSubstitution: false,
                     automaticDashSubstitution: false,
                     automaticSymbolBalancing: false,
                     continuousSpellChecking: true,