By default, VSCode will try to guess your indentation options depending on the file you open.
You can turn off indentation guessing via "editor.detectIndentation": false
You can customize this easily via these 3 settings in File > Preferences > User Settings:
// The number of spaces a tab is equal to. This setting is overriden // based on the file contents when `editor.detectIndentation` is true. "editor.tabSize": 4, // Insert spaces when pressing Tab. This setting is overriden // based on the file contents when `editor.detectIndentation` is true. "editor.insertSpaces": true, // When opening a file, `editor.tabSize` and `editor.insertSpaces` // will be detected based on the file contents. Set to false to keep // the values you've explicitly set, above. "editor.detectIndentation": false 