diff --git a/Sources/Generator/Generators/PageContentGenerator.swift b/Sources/Generator/Generators/PageContentGenerator.swift
index aea5ef2..14a90ad 100644
--- a/Sources/Generator/Generators/PageContentGenerator.swift
+++ b/Sources/Generator/Generators/PageContentGenerator.swift
@@ -278,7 +278,10 @@ struct PageContentGenerator {
                     results.warning("Invalid external link definition", source: page.path)
                     return nil
                 }
-                let url = parts[0].trimmed
+                guard let url = parts[0].trimmed.addingPercentEncoding(withAllowedCharacters: .urlQueryAllowed) else {
+                    results.warning("Invalid external link \(parts[0].trimmed)", source: page.path)
+                    return nil
+                }
                 let title = parts[1].trimmed
 
                 return (url, title)