diff --git a/sasmodels/generate.py b/sasmodels/generate.py
index e0c32ea2..3014dd9b 100644
--- a/sasmodels/generate.py
+++ b/sasmodels/generate.py
@@ -661,7 +661,7 @@ def load_template(filename):
     path = joinpath(DATA_PATH, filename)
     mtime = getmtime(path)
     if filename not in _template_cache or mtime > _template_cache[filename][0]:
-        with open(path) as fid:
+        with open(path, encoding="utf-8") as fid:
             _template_cache[filename] = (mtime, fid.read(), path)
     return _template_cache[filename][1], path
 
@@ -945,7 +945,10 @@ def _add_source(source, code, path, lineno=1):
     source.append(code)
 
 def read_text(f):
-    with open(f) as fid:
+    """
+    Read a source file. Sources are UTF-8.
+    """
+    with open(f, encoding="utf-8") as fid:
         return fid.read()
 
 def make_source(model_info):
diff --git a/sasmodels/gengauss.py b/sasmodels/gengauss.py
index 2ef06313..22227896 100755
--- a/sasmodels/gengauss.py
+++ b/sasmodels/gengauss.py
@@ -20,7 +20,7 @@ def gengauss(n, path):
     else:
         array_size = n
 
-    with open(path, "w") as fid:
+    with open(path, "w", encoding="utf-8") as fid:
         fid.write(f"""\
 // Generated by sasmodels.gengauss.gengauss({n})
 
diff --git a/sasmodels/kerneldll.py b/sasmodels/kerneldll.py
index 216b668d..2653c1ef 100644
--- a/sasmodels/kerneldll.py
+++ b/sasmodels/kerneldll.py
@@ -293,12 +293,12 @@ def make_dll(source, model_info, dtype=F64, system=False):
             basename = splitext(os.path.basename(dll))[0] + "_"
             system_fd, filename = tempfile.mkstemp(suffix=".c", prefix=basename)
             logging.debug("make_dll: writing C for dll: %s", filename)
-            with os.fdopen(system_fd, "w") as file_handle:
+            with os.fdopen(system_fd, "w", encoding="utf-8") as file_handle:
                 file_handle.write(source)
         else:
             filename = splitext(dll)[0] + ".c"
             logging.debug("make_dll: writing C for system dll: %s", filename)
-            with open(filename, 'w') as file_handle:
+            with open(filename, 'w', encoding="utf-8") as file_handle:
                 file_handle.write(source)
         compile_model(source=filename, output=dll)
         # Comment the following to keep the generated C file.
diff --git a/sasmodels/rst2html.py b/sasmodels/rst2html.py
index cd71c3ee..971c2e51 100644
--- a/sasmodels/rst2html.py
+++ b/sasmodels/rst2html.py
@@ -145,7 +145,7 @@ def load_rst_as_html(filename):
     # type: (str) -> str
     """Load rst from file and convert to html"""
     from os.path import expanduser
-    with open(expanduser(filename)) as fid:
+    with open(expanduser(filename), encoding="utf-8") as fid:
         rst = fid.read()
     html = rst2html(rst)
     return html