diff --git a/cosmic-theme/src/output/mod.rs b/cosmic-theme/src/output/mod.rs
index 0e14108d..2f7cfa7d 100644
--- a/cosmic-theme/src/output/mod.rs
+++ b/cosmic-theme/src/output/mod.rs
@@ -17,6 +17,8 @@ pub enum OutputError {
     Io(std::io::Error),
     #[error("Missing config directory")]
     MissingConfigDir,
+    #[error("Missing data directory")]
+    MissingDataDir,
     #[error("Serde Error: {0}")]
     Serde(#[from] serde_json::Error),
 }
diff --git a/cosmic-theme/src/output/qt_output.rs b/cosmic-theme/src/output/qt_output.rs
index 1c9d1c08..fbde8a9d 100644
--- a/cosmic-theme/src/output/qt_output.rs
+++ b/cosmic-theme/src/output/qt_output.rs
@@ -14,7 +14,7 @@ impl Theme {
     #[cold]
     /// Some high-level documentation for this file can be found at:
     /// https://web.archive.org/web/20250402234329/https://docs.kde.org/stable5/en/plasma-workspace/kcontrol/colors/
-    pub fn as_qt_color_scheme(&self) -> String {
+    pub fn as_qt(&self) -> String {
         let mut output = "# GENERATED BY COSMIC\n".to_string();
 
         // Usually, disabled elements will have strongly reduced contrast and are often notably darker or lighter
@@ -179,10 +179,136 @@ inactiveForeground=161,169,177
 
         output
     }
+
+    /// Write the color scheme to the appropriate directory.
+    /// Should be written in `~/.local/share/color-schemes/`.
+    ///
+    /// See the docs: https://develop.kde.org/docs/plasma/#color-scheme
+    ///
+    /// # Errors
+    ///
+    /// Returns an `OutputError` if there is an error writing the colors file.
+    #[cold]
+    pub fn write_qt(&self) -> Result<(), OutputError> {
+        let colors = self.as_qt();
+        let Some(mut data_dir) = dirs::data_dir() else {
+            return Err(OutputError::MissingDataDir);
+        };
+
+        let file_name = if self.is_dark {
+            "CosmicDark.colors"
+        } else {
+            "CosmicLight.colors"
+        };
+
+        data_dir.push("color-schemes");
+        if !data_dir.exists() {
+            std::fs::create_dir_all(&data_dir).map_err(OutputError::Io)?;
+        }
+
+        let mut file = File::create(data_dir.join(file_name)).map_err(OutputError::Io)?;
+        file.write_all(colors.as_bytes()).map_err(OutputError::Io)?;
+
+        Ok(())
+    }
+
+    /// Apply the color scheme by copying it to `~/.config/kdeglobals`.
+    ///
+    /// See the docs: https://develop.kde.org/docs/plasma/#color-scheme
+    ///
+    /// # Errors
+    ///
+    /// Returns an `OutputError` if there is an error applying the color scheme.
+    #[cold]
+    pub fn apply_qt(is_dark: bool) -> Result<(), OutputError> {
+        let Some(config_dir) = dirs::config_dir() else {
+            return Err(OutputError::MissingConfigDir);
+        };
+        let Some(mut data_dir) = dirs::data_dir() else {
+            return Err(OutputError::MissingDataDir);
+        };
+        data_dir.push("color-schemes");
+
+        let src_file = data_dir.join(if is_dark {
+            "CosmicDark.colors"
+        } else {
+            "CosmicLight.colors"
+        });
+
+        let dest_file = config_dir.join("kdeglobals");
+
+        #[cfg(target_family = "unix")]
+        {
+            use std::os::unix::fs::symlink;
+            Self::backup_non_cosmic_kdeglobals(&dest_file).map_err(OutputError::Io)?;
+
+            if dest_file.exists() {
+                // Currently we overwrite the file with our symlink.
+                // Maybe in the future we could merge kdeglobals with our color scheme ini?
+                fs::remove_file(&dest_file).map_err(OutputError::Io)?;
+            }
+
+            symlink(src_file, dest_file).map_err(OutputError::Io)?
+        }
+
+        Ok(())
+    }
+
+    /// Reset the applied qt colors by deleting the `~/.config/kdeglobals` file.
+    ///
+    /// This does not restore the backed up kdeglobals file.
+    ///
+    /// # Errors
+    ///
+    /// Returns an `OutputError` if there is an error resetting the CSS file.
+    #[cold]
+    pub fn reset_qt() -> Result<(), OutputError> {
+        let Some(config_dir) = dirs::config_dir() else {
+            return Err(OutputError::MissingConfigDir);
+        };
+        let dest_file = config_dir.join("kdeglobals");
+
+        if Self::is_cosmic_kdeglobals(&dest_file).map_err(OutputError::Io)?.unwrap_or_default() {
+            fs::remove_file(dest_file).map_err(OutputError::Io)?
+        }
+        Ok(())
+    }
+
+    #[cold]
+    fn backup_non_cosmic_kdeglobals(path: &Path) -> io::Result<()> {
+        if !Self::is_cosmic_kdeglobals(path)?.unwrap_or(true) {
+            let backup_path = path.with_extension("bak");
+            fs::rename(path, &backup_path)?;
+        }
+        Ok(())
+    }
+
+    #[cold]
+    fn is_cosmic_kdeglobals(path: &Path) -> io::Result<Option<bool>> {
+        if !path.exists() {
+            return Ok(None);
+        }
+
+        if let Ok(metadata) = fs::symlink_metadata(path) {
+            if !metadata.file_type().is_symlink() {
+                return Ok(Some(false));
+            }
+            let Ok(target) = fs::read_link(path) else {
+                return Ok(Some(false));
+            };
+            let Some(target_filename) = target.file_name() else {
+                return Ok(Some(false));
+            };
+            return Ok(Some(
+                target_filename == "CosmicDark.colors" || target_filename == "CosmicLight.colors",
+            ));
+        }
+        Ok(Some(false))
+    }
 }
 
 /// Formats a color in the form `r,g,b` e.g. `255,255,255`
-pub fn to_rgb(c: Srgba) -> String {
+fn to_rgb(c: Srgba) -> String {
     let c_u8: Rgba<palette::encoding::Srgb, u8> = c.into_format();
     format!("{},{},{}", c_u8.red, c_u8.green, c_u8.blue)
 }