diff --git a/rmgpy/constraints.py b/rmgpy/constraints.py
index be7f950f4ce..2f2aa56c5ea 100644
--- a/rmgpy/constraints.py
+++ b/rmgpy/constraints.py
@@ -141,4 +141,9 @@ def fails_species_constraints(species):
         if struct.get_singlet_carbene_count() > 0 and struct.get_radical_count() > max_carbene_radicals:
             return True
 
+    max_fused_rings = species_constraints.get('maximumFusedRings', -1)
+    if max_fused_rings != -1 and struct.is_cyclic():
+        if struct.get_ring_count_in_largest_fused_ring_system() > max_fused_rings:
+            return True
+
     return False
diff --git a/rmgpy/rmg/input.py b/rmgpy/rmg/input.py
index e04cd82e2ed..bf450f90b35 100644
--- a/rmgpy/rmg/input.py
+++ b/rmgpy/rmg/input.py
@@ -1379,6 +1379,7 @@ def generated_species_constraints(**kwargs):
         'maximumRadicalElectrons',
         'maximumSingletCarbenes',
         'maximumCarbeneRadicals',
+        'maximumFusedRings',
         'allowSingletO2',
         'speciesCuttingThreshold',
     ]