diff --git a/pytket/conanfile.py b/pytket/conanfile.py
index 80e7e0b31c..3cc45a02ff 100644
--- a/pytket/conanfile.py
+++ b/pytket/conanfile.py
@@ -38,7 +38,7 @@ def requirements(self):
         self.requires("pybind11_json/0.2.14")
         self.requires("symengine/0.12.0")
         self.requires("tkassert/0.3.4@tket/stable")
-        self.requires("tket/1.3.35@tket/stable")
+        self.requires("tket/1.3.36@tket/stable")
         self.requires("tklog/0.3.3@tket/stable")
         self.requires("tkrng/0.3.3@tket/stable")
         self.requires("tktokenswap/0.3.9@tket/stable")
diff --git a/pytket/docs/changelog.rst b/pytket/docs/changelog.rst
index 143d5592c8..a092356c1d 100644
--- a/pytket/docs/changelog.rst
+++ b/pytket/docs/changelog.rst
@@ -1,6 +1,13 @@
 Changelog
 =========
 
+Unreleased
+----------
+
+Fixes:
+
+* Fix `symbol_substitution` not preserving opgroups.
+
 1.34.0 (October 2024)
 ---------------------
 
diff --git a/tket/conanfile.py b/tket/conanfile.py
index 6439e45b7a..a131da11e2 100644
--- a/tket/conanfile.py
+++ b/tket/conanfile.py
@@ -23,7 +23,7 @@
 
 class TketConan(ConanFile):
     name = "tket"
-    version = "1.3.35"
+    version = "1.3.36"
     package_type = "library"
     license = "Apache 2"
     homepage = "https://github.com/CQCL/tket"
diff --git a/tket/src/Circuit/Circuit.cpp b/tket/src/Circuit/Circuit.cpp
index e85292b2b6..115880b746 100644
--- a/tket/src/Circuit/Circuit.cpp
+++ b/tket/src/Circuit/Circuit.cpp
@@ -177,7 +177,7 @@ void Circuit::symbol_substitution(const SymEngine::map_basic_basic sub_map) {
   BGL_FORALL_VERTICES(v, dag, DAG) {
     Op_ptr new_op = get_Op_ptr_from_Vertex(v)->symbol_substitution(sub_map);
     if (new_op) {
-      dag[v] = {new_op};
+      dag[v] = {new_op, dag[v].opgroup};
     }
   }
   phase = phase.subs(sub_map);
diff --git a/tket/test/src/Circuit/test_Circ.cpp b/tket/test/src/Circuit/test_Circ.cpp
index 0575e382c7..e868668bd9 100644
--- a/tket/test/src/Circuit/test_Circ.cpp
+++ b/tket/test/src/Circuit/test_Circ.cpp
@@ -22,6 +22,7 @@
 #include "../testutil.hpp"
 #include "tket/Circuit/Circuit.hpp"
 #include "tket/Circuit/DAGDefs.hpp"
+#include "tket/Circuit/PauliExpBoxes.hpp"
 #include "tket/Circuit/Simulation/CircuitSimulator.hpp"
 #include "tket/Gate/GatePtr.hpp"
 #include "tket/Gate/OpPtrFunctions.hpp"
@@ -1292,6 +1293,36 @@ SCENARIO("Functions with symbolic ops") {
     REQUIRE(test_equiv_val(op2->get_params()[0], 0.2));
     REQUIRE(op3->get_type() == OpType::Barrier);
   }
+  GIVEN("A circuit with symbolic gates and boxes that belong to opgroups.") {
+    Sym asym = SymEngine::symbol("a");
+    Expr alpha(asym);
+    Sym bsym = SymEngine::symbol("b");
+    Expr beta(bsym);
+    Circuit circ(2);
+    circ.add_op<unsigned>(OpType::Rx, alpha, {0}, "Rx");
+    Circuit inner_circ(2);
+    inner_circ.add_op<unsigned>(OpType::Rx, {alpha}, {0});
+    inner_circ.add_op<unsigned>(OpType::Ry, {beta}, {0});
+    auto cbox = CircBox(inner_circ);
+    circ.add_box(cbox, {0, 1}, "cbox");
+    DensePauliMap paulis0{Pauli::X, Pauli::X};
+    DensePauliMap paulis1{Pauli::Z, Pauli::X};
+    auto ppbox = PauliExpPairBox(
+        SymPauliTensor(paulis0, alpha), SymPauliTensor(paulis1, beta));
+    circ.add_box(ppbox, {0, 1}, "ppbox");
+    symbol_map_t symbol_map;
+    symbol_map[asym] = Expr(0.2);
+    symbol_map[bsym] = Expr(0.3);
+    circ.symbol_substitution(symbol_map);
+    REQUIRE(!circ.is_symbolic());
+    std::unordered_set<std::string> opgroups({"Rx", "cbox", "ppbox"});
+    REQUIRE(circ.get_opgroups() == opgroups);
+    std::vector<Command> cmds = circ.get_commands();
+    REQUIRE(cmds.size() == 3);
+    REQUIRE(cmds[0].get_opgroup().value() == "Rx");
+    REQUIRE(cmds[1].get_opgroup().value() == "cbox");
+    REQUIRE(cmds[2].get_opgroup().value() == "ppbox");
+  }
 }
 
 SCENARIO("Test depth_by_type method") {