diff --git a/pkgs/pkgs-lib/formats/hocon/default.nix b/pkgs/pkgs-lib/formats/hocon/default.nix
index d7ff1e85bda6..55354ddbd600 100644
--- a/pkgs/pkgs-lib/formats/hocon/default.nix
+++ b/pkgs/pkgs-lib/formats/hocon/default.nix
@@ -70,10 +70,10 @@ in
           }
         else
           assert lib.assertMsg (lib.isAttrs value) ''
-            Value of invalid type provided to `hocon.lib.mkSubstition`: ${lib.typeOf value}
+            Value of invalid type provided to `hocon.lib.mkSubstitution`: ${lib.typeOf value}
           '';
           assert lib.assertMsg (value ? "value") ''
-            Argument to `hocon.lib.mkSubstition` is missing a `value`:
+            Argument to `hocon.lib.mkSubstitution` is missing a `value`:
             ${builtins.toJSON value}
           '';
           {
diff --git a/pkgs/pkgs-lib/formats/hocon/src/src/main.rs b/pkgs/pkgs-lib/formats/hocon/src/src/main.rs
index 2e53f3fd5659..6809ed739159 100644
--- a/pkgs/pkgs-lib/formats/hocon/src/src/main.rs
+++ b/pkgs/pkgs-lib/formats/hocon/src/src/main.rs
@@ -77,12 +77,12 @@ fn parse_special_types(o: &Map<String, Value>) -> Option<HOCONValue> {
                     .get("value")
                     .expect("Missing value for substitution")
                     .as_str()
-                    .unwrap_or_else(|| panic!("Substition value is not a string: {:?}", o));
+                    .unwrap_or_else(|| panic!("Substitution value is not a string: {:?}", o));
                 let required = o
                     .get("required")
                     .unwrap_or(&Value::Bool(false))
                     .as_bool()
-                    .unwrap_or_else(|| panic!("Substition value is not a string: {:?}", o));
+                    .unwrap_or_else(|| panic!("Substitution value is not a string: {:?}", o));
 
                 debug_assert!(!value.contains('}'));