diff --git a/src/ifcgeom/mapping/mapping.cpp b/src/ifcgeom/mapping/mapping.cpp
index 0ed5af5396..42c41c1f99 100644
--- a/src/ifcgeom/mapping/mapping.cpp
+++ b/src/ifcgeom/mapping/mapping.cpp
@@ -1283,26 +1283,59 @@ void mapping::addRepresentationsFromDefaultContexts(std::vector<IfcSchema::IfcRe
     }
 }
 
-express::Base mapping::representation_of(const express::Base& product) {
-    // @todo correct, but very inefficient
-    std::vector<IfcSchema::IfcRepresentation> representations;
-    std::vector<IfcSchema::IfcRepresentation> of_product;
-    std::vector<IfcSchema::IfcRepresentation> intersection;
-    std::vector<IfcSchema::IfcRepresentation> intersection_no_box;
+void mapping::ensureRepresentationContextCache_() {
+    const auto has_context_ids = settings_.get<settings::ContextIds>().has();
+    const auto dimensionality = settings_.get<settings::OutputDimensionality>().get();
+    const auto context_ids = has_context_ids ? settings_.get<settings::ContextIds>().get() : std::set<int>{};
 
-    if (!settings_.get<settings::ContextIds>().has()) {
+    std::lock_guard<std::mutex> guard(representation_context_cache_guard_);
+
+    if (representation_context_cache_valid_ &&
+        representation_context_cache_has_context_ids_ == has_context_ids &&
+        representation_context_cache_dimensionality_ == dimensionality &&
+        representation_context_cache_ids_ == context_ids) {
+        return;
+    }
+
+    std::vector<IfcSchema::IfcRepresentation> representations;
+    if (!has_context_ids) {
         addRepresentationsFromDefaultContexts(representations);
     } else {
         addRepresentationsFromContextIds(representations);
     }
 
+    std::unordered_set<uint32_t> representation_ids;
+    representation_ids.reserve(representations.size());
+    for (auto& representation : representations) {
+        if (representation) {
+            representation_ids.insert((uint32_t)representation.id());
+        }
+    }
+
+    representation_context_cache_ = std::move(representation_ids);
+    representation_context_cache_ids_ = std::move(context_ids);
+    representation_context_cache_dimensionality_ = dimensionality;
+    representation_context_cache_has_context_ids_ = has_context_ids;
+    representation_context_cache_valid_ = true;
+}
+
+express::Base mapping::representation_of(const express::Base& product) {
+    std::vector<IfcSchema::IfcRepresentation> of_product;
+    std::vector<IfcSchema::IfcRepresentation> intersection;
+    std::vector<IfcSchema::IfcRepresentation> intersection_no_box;
+
+    ensureRepresentationContextCache_();
+
     if (product.as<IfcSchema::IfcProduct>().Representation()) {
         of_product = product.as<IfcSchema::IfcProduct>().Representation().Representations();
     }
 
-    for (auto& r : of_product) {
-        if (std::find(representations.begin(), representations.end(), r) != representations.end()) {
-            intersection.push_back(r);
+    {
+        std::lock_guard<std::mutex> guard(representation_context_cache_guard_);
+        for (auto& r : of_product) {
+            if (representation_context_cache_.find((uint32_t)r.id()) != representation_context_cache_.end()) {
+                intersection.push_back(r);
+            }
         }
     }
 
diff --git a/src/ifcgeom/mapping/mapping.h b/src/ifcgeom/mapping/mapping.h
index 0638fd6dbc..1055fe093b 100644
--- a/src/ifcgeom/mapping/mapping.h
+++ b/src/ifcgeom/mapping/mapping.h
@@ -7,6 +7,7 @@
 #include "../../ifcparse/logger.h"
 
 #include <mutex>
+#include <unordered_set>
 
 #define INCLUDE_SCHEMA(x) STRINGIFY(../../ifcparse/schemas/x.h)
 #include INCLUDE_SCHEMA(IfcSchema)
@@ -36,11 +37,18 @@ namespace geometry {
 		void initialize_units_();
 		void addRepresentationsFromContextIds(std::vector<IfcSchema::IfcRepresentation>&);
 		void addRepresentationsFromDefaultContexts(std::vector<IfcSchema::IfcRepresentation>&);
+		void ensureRepresentationContextCache_();
 
 		// Set of instances to mark failures that are intended, such as representations not
 		// resulting in any items due to dimensionality filters.
 		std::set<express::Base> failed_on_purpose_;
 		std::set<IfcSchema::IfcRepresentationMap> not_reusable_maps_;
+		std::unordered_set<uint32_t> representation_context_cache_;
+		std::set<int> representation_context_cache_ids_;
+		settings::OutputDimensionalityTypes representation_context_cache_dimensionality_ = settings::SURFACES_AND_SOLIDS;
+		bool representation_context_cache_has_context_ids_ = false;
+		bool representation_context_cache_valid_ = false;
+		std::mutex representation_context_cache_guard_;
 
 		template <typename T>
 		void process_mapping(bool& matched, taxonomy::ptr& item, const express::Base& inst) {
@@ -152,4 +160,4 @@ namespace geometry {
 
 }
 
-#endif
\ No newline at end of file
+#endif