diff --git a/CHANGELOG.md b/CHANGELOG.md
index f3e6eb787870..8c6226975a25 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -40,6 +40,7 @@ Compatibility:
 * Add `Dir.for_fd` (#3681, @andrykonchin).
 * Add `Dir.fchdir` (#3681, @andrykonchin).
 * Add `Dir#chdir` (#3681, @andrykonchin).
+* Declare `File::SHARE_DELETE` constant (#3745, @andrykonchin).
 
 Performance:
 
diff --git a/spec/ruby/core/file/constants/constants_spec.rb b/spec/ruby/core/file/constants/constants_spec.rb
index 86946822c56f..bba248c21e20 100644
--- a/spec/ruby/core/file/constants/constants_spec.rb
+++ b/spec/ruby/core/file/constants/constants_spec.rb
@@ -4,7 +4,7 @@
   "FNM_DOTMATCH", "FNM_EXTGLOB", "FNM_NOESCAPE", "FNM_PATHNAME",
   "FNM_SYSCASE", "LOCK_EX", "LOCK_NB", "LOCK_SH",
   "LOCK_UN", "NONBLOCK", "RDONLY",
-  "RDWR", "TRUNC", "WRONLY"].each do |const|
+  "RDWR", "TRUNC", "WRONLY", "SHARE_DELETE"].each do |const|
   describe "File::Constants::#{const}" do
     it "is defined" do
       File::Constants.const_defined?(const).should be_true
diff --git a/src/main/ruby/truffleruby/core/file.rb b/src/main/ruby/truffleruby/core/file.rb
index b814fa9e1ff4..eb70712b40e9 100644
--- a/src/main/ruby/truffleruby/core/file.rb
+++ b/src/main/ruby/truffleruby/core/file.rb
@@ -82,6 +82,8 @@ module Constants
     NONBLOCK = Truffle::Config['platform.file.O_NONBLOCK']
     SYNC     = Truffle::Config['platform.file.O_SYNC']
 
+    SHARE_DELETE   = 0 # a pseudo file mode flag that's meaningful only on Windows
+
     if value = Truffle::Config.lookup('platform.file.O_TMPFILE')
       TMPFILE = value
     end