diff --git a/src/libraries/System.Formats.Tar/tests/TarWriter/TarWriter.WriteEntry.LongFile.Tests.cs b/src/libraries/System.Formats.Tar/tests/TarWriter/TarWriter.WriteEntry.LongFile.Tests.cs
index 6fd2166e81c35f..41e0a61005112a 100644
--- a/src/libraries/System.Formats.Tar/tests/TarWriter/TarWriter.WriteEntry.LongFile.Tests.cs
+++ b/src/libraries/System.Formats.Tar/tests/TarWriter/TarWriter.WriteEntry.LongFile.Tests.cs
@@ -86,6 +86,7 @@ public void WriteEntry_LongFileSize(TarEntryFormat entryFormat, long size, bool
             Assert.Equal(size, dataStream.Position);
 
             Assert.Null(reader.GetNextEntry());
+            tarFile.Close();
         }
     }
 }
diff --git a/src/libraries/System.Formats.Tar/tests/TarWriter/TarWriter.WriteEntryAsync.LongFile.Tests.cs b/src/libraries/System.Formats.Tar/tests/TarWriter/TarWriter.WriteEntryAsync.LongFile.Tests.cs
index 0f6202662d6097..ce8c4a4f945b6c 100644
--- a/src/libraries/System.Formats.Tar/tests/TarWriter/TarWriter.WriteEntryAsync.LongFile.Tests.cs
+++ b/src/libraries/System.Formats.Tar/tests/TarWriter/TarWriter.WriteEntryAsync.LongFile.Tests.cs
@@ -76,6 +76,7 @@ public async Task WriteEntry_LongFileSizeAsync(TarEntryFormat entryFormat, long
             Assert.Equal(size, dataStream.Position);
 
             Assert.Null(await reader.GetNextEntryAsync());
+            tarFile.Close();
         }
     }
 }