diff --git a/src/scanner.rs b/src/scanner.rs
index e82ec26..981b0c9 100644
--- a/src/scanner.rs
+++ b/src/scanner.rs
@@ -85,6 +85,8 @@ impl Scanner {
                     while self.peek() != '\n' && !self.is_at_end() {
                         self.current += 1;
                     }
+                } else if self.is_match('*') {
+                    self.block_comment(err_hdl);
                 } else {
                     self.add_token(TokenType::Slash)
                 }
@@ -195,6 +197,32 @@ impl Scanner {
         }
     }
 
+    /// Read (and ignore) a block comment. Block comments may be nested.
+    fn block_comment(&mut self, err_hdl: &mut ErrorHandler) {
+        let mut depth = 1;
+        loop {
+            if self.is_at_end() {
+                err_hdl.error(self.line, "unterminated block comment");
+                return
+            }
+
+            let cur = self.advance();
+            let next = self.peek();
+            if cur == '*' && next == '/' {
+                depth -= 1;
+                self.current += 1;
+                if depth == 0 {
+                    return;
+                }
+            } else if cur == '/' && next == '*' {
+                depth += 1;
+                self.current += 1;
+            } else if cur == '\n' {
+                self.line += 1;
+            }
+        }
+    }
+
     /// Check whether the end of the input has been reached.
     fn is_at_end(&self) -> bool {
         self.current >= self.len