diff --git a/pyxdsm/XDSM.py b/pyxdsm/XDSM.py
index 392cd66..9fa63d0 100644
--- a/pyxdsm/XDSM.py
+++ b/pyxdsm/XDSM.py
@@ -117,7 +117,16 @@ def _label_to_spec(label, spec):
 
 
 class XDSM(object):
-    def __init__(self, use_sfmath=True):
+    def __init__(self, use_sfmath=True, optional_latex_packages=None):
+        """Initialize XDSM object
+
+        Parameters
+        ----------
+        use_sfmath : bool, optional
+            Whether to use the sfmath latex package, by default True
+        optional_latex_packages : string or list of strings, optional
+            Additional latex packages to use when creating the pdf and tex versions of the diagram, by default None
+        """
         self.systems = []
         self.connections = []
         self.left_outs = {}
@@ -127,6 +136,15 @@ def __init__(self, use_sfmath=True):
         self.process_arrows = []
 
         self.use_sfmath = use_sfmath
+        if optional_latex_packages is None:
+            self.optional_packages = []
+        else:
+            if isinstance(optional_latex_packages, str):
+                self.optional_packages = [optional_latex_packages]
+            elif isinstance(optional_latex_packages, list):
+                self.optional_packages = optional_latex_packages
+            else:
+                raise ValueError("optional_latex_packages must be a string or a list of strings")
 
     def add_system(
         self,
@@ -502,7 +520,7 @@ def _build_process_chain(self):
     def _compose_optional_package_list(self):
 
         # Check for optional LaTeX packages
-        optional_packages_list = []
+        optional_packages_list = self.optional_packages
         if self.use_sfmath:
             optional_packages_list.append("sfmath")