diff --git a/crates/zensical/src/config.rs b/crates/zensical/src/config.rs
index 404f5db..bb9f656 100644
--- a/crates/zensical/src/config.rs
+++ b/crates/zensical/src/config.rs
@@ -112,6 +112,7 @@ impl Config {
             let hash = {
                 let mut hasher = DefaultHasher::default();
                 project.hash(&mut hasher);
+                hasher.write_u64(project.template_hash);
                 hasher.finish()
             };
 
diff --git a/crates/zensical/src/config/project.rs b/crates/zensical/src/config/project.rs
index 5aaa322..b9b8140 100644
--- a/crates/zensical/src/config/project.rs
+++ b/crates/zensical/src/config/project.rs
@@ -88,4 +88,6 @@ pub struct Project {
     pub plugins: Plugins,
     /// Navigation structure.
     pub nav: Vec<NavigationItem>,
+    /// Template hash.
+    pub template_hash: u64,
 }
diff --git a/crates/zensical/src/watcher.rs b/crates/zensical/src/watcher.rs
index e7f4980..c15740c 100644
--- a/crates/zensical/src/watcher.rs
+++ b/crates/zensical/src/watcher.rs
@@ -27,6 +27,7 @@
 
 use crossbeam::channel::Sender;
 use mio::Waker;
+use std::collections::BTreeSet;
 use std::fs;
 use std::path::PathBuf;
 use std::sync::Arc;
@@ -78,9 +79,11 @@ impl Watcher {
         sources.push((config.get_site_dir(), config.project.site_dir.clone()));
         sources.push((path, String::from(".")));
 
+        // Track seen files to restart on config or template change
+        let mut seen = BTreeSet::new();
+
         // Initialize file agent - we use a debounce interval of 20ms, which
         // should be sufficient to correctly determine rename events
-        let mut initial = false;
         let agent = Agent::new(Duration::from_millis(20), {
             let config = config.clone();
             move |res| {
@@ -93,11 +96,20 @@ impl Watcher {
 
                     // Check if the config file reloaded, and terminate agent,
                     // as we need to kick off the entire pipeline again
-                    if *event.path() == config.path {
-                        if initial {
+                    if *event.path() == config.path
+                        && !seen.insert(config.path.clone())
+                    {
+                        return Err(Error::Disconnected);
+                    }
+
+                    // Check if the event is in any of the theme directories
+                    // and restart the build if we've already seen the file
+                    for dir in &config.theme_dirs {
+                        if event.path().starts_with(dir)
+                            && !seen.insert((*event.path()).clone())
+                        {
                             return Err(Error::Disconnected);
                         }
-                        initial = true;
                     }
 
                     // Ignore events in the site directory, since they are files
diff --git a/python/zensical/config.py b/python/zensical/config.py
index 465ec75..0d52230 100644
--- a/python/zensical/config.py
+++ b/python/zensical/config.py
@@ -118,6 +118,12 @@ def get_theme_dir() -> str:
     return os.path.join(path, "templates")
 
 
+def get_custom_theme_dir(config: dict) -> str | None:
+    """Return the custom theme directory."""
+    path = os.path.dirname(os.path.abspath(__file__))
+    return os.path.join(path, config["theme"]["custom_dir"])
+
+
 def _apply_defaults(config: dict, path: str) -> dict:
     """Apply default settings in configuration.
 
@@ -424,6 +430,8 @@ def _apply_defaults(config: dict, path: str) -> dict:
             config["markdown_extensions"].append("mkdocstrings")
             config["mdx_configs"]["mkdocstrings"] = mkdocstrings_config
 
+    # Hash all templates, so we rebuild if something changes
+    config["template_hash"] = _hash(_list_templates(config))
     return config
 
 
@@ -456,6 +464,29 @@ def _hash(data: Any) -> int:
     return int(hash.hexdigest(), 16) % (2**64)
 
 
+def _list_templates(config: dict) -> list[tuple[str, int]]:
+    """List all template files in the theme directories."""
+    dirs = [get_theme_dir()]
+    if "custom_dir" in config["theme"]:
+        custom_dir = get_custom_theme_dir(config)
+        if custom_dir is not None:
+            dirs.append(custom_dir)
+
+    # Collect file paths and their mtimes
+    files_with_mtime = []
+    for directory in dirs:
+        for path, _, files in os.walk(directory):
+            if ".icons" in path:
+                continue
+            for file in files:
+                file_path = os.path.join(path, file)
+                mtime = os.path.getsize(file_path)
+                files_with_mtime.append((file_path, mtime))
+
+    # Sort by file path for deterministic order
+    return sorted(files_with_mtime)
+
+
 def _convert_extra(data: dict | list) -> dict | list:
     """Recursively convert all None values in a dictionary or list to empty strings."""
     if isinstance(data, dict):