diff --git a/ruby/scripts/generate-metadata.rb b/ruby/scripts/generate-metadata.rb
index 8bd40a3514..2d41a5dd68 100755
--- a/ruby/scripts/generate-metadata.rb
+++ b/ruby/scripts/generate-metadata.rb
@@ -14,7 +14,9 @@ class MetadataExtractor
   METHODS = %w[get post put patch delete].freeze
 
   def initialize(openapi_path)
-    @openapi = JSON.parse(File.read(openapi_path))
+    # Read as UTF-8 regardless of process locale (LC_ALL=C would otherwise read
+    # as US-ASCII and JSON.parse dies on the spec's multibyte characters)
+    @openapi = JSON.parse(File.read(openapi_path, encoding: 'UTF-8'))
   end
 
   def extract
diff --git a/ruby/scripts/generate-services.rb b/ruby/scripts/generate-services.rb
index 71eb8733d0..b898e7ffcf 100644
--- a/ruby/scripts/generate-services.rb
+++ b/ruby/scripts/generate-services.rb
@@ -321,7 +321,8 @@ def download(upload_id:)
   ].freeze
 
   def initialize(openapi_path)
-    @openapi = JSON.parse(File.read(openapi_path))
+    # UTF-8 regardless of process locale — see generate-metadata.rb
+    @openapi = JSON.parse(File.read(openapi_path, encoding: 'UTF-8'))
     @schemas = @openapi.dig('components', 'schemas') || {}
   end
 
diff --git a/ruby/scripts/generate-types.rb b/ruby/scripts/generate-types.rb
index 1d012d9f85..f4dfbc4bf0 100755
--- a/ruby/scripts/generate-types.rb
+++ b/ruby/scripts/generate-types.rb
@@ -131,7 +131,8 @@ def deprecation_doc_lines(reason, indent:, tag_prefix: '')
   puts '  module Types'
   puts '    include TypeHelpers'
 
-  schemas = JSON.parse(File.read(openapi_path))['components']['schemas'] || {}
+  # UTF-8 regardless of process locale — see generate-metadata.rb
+  schemas = JSON.parse(File.read(openapi_path, encoding: 'UTF-8'))['components']['schemas'] || {}
   sorted = schemas.keys.sort
 
   sorted.each do |name|