diff --git a/include/ice_transport_factory.h b/include/ice_transport_factory.h
index df3367c..3e4c931 100644
--- a/include/ice_transport_factory.h
+++ b/include/ice_transport_factory.h
@@ -19,6 +19,7 @@
 #include "ice_options.h"
 #include "ice_transport.h"
 #include "ip_utils.h"
+#include "pj_init_lock.h"
 
 #include <functional>
 #include <memory>
@@ -50,6 +51,9 @@
     std::shared_ptr<pj_caching_pool> getPoolCaching() { return cp_; }
 
 private:
+    // Declaring pjInitLock_ before cp_ because its constructor needs to be called
+    // first (see constructor implementation for a comment with more information).
+    PjInitLock pjInitLock_;
     std::shared_ptr<pj_caching_pool> cp_;
     pj_ice_strans_cfg ice_cfg_;
     std::shared_ptr<Logger> logger_ {};
diff --git a/include/pj_init_lock.h b/include/pj_init_lock.h
new file mode 100644
index 0000000..c521a8a
--- /dev/null
+++ b/include/pj_init_lock.h
@@ -0,0 +1,59 @@
+/*
+ *  Copyright (C) 2024 Savoir-faire Linux Inc.
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program. If not, see <https://www.gnu.org/licenses/>.
+ */
+#pragma once
+
+#include <fmt/core.h>
+#include <mutex>
+#include <pj/errno.h>
+#include <pj/types.h>
+
+namespace dhtnet {
+
+// PJSIP expects the number of calls to pj_shutdown to match the number of calls
+// to pj_init (https://docs.pjsip.org/en/latest/specific-guides/develop/init_shutdown_thread.html).
+// The intended behavior seems to be the following:
+// - The first call to pj_init actually initializes the library; subsequent calls do nothing.
+// - All calls to pj_shutdown do nothing, except the last one which actually performs the shutdown.
+// Unfortunately, the way this logic is implemented in PJSIP is not thread-safe, so we're
+// responsible for making sure that these functions can't be called by two threads at the same time.
+class PjInitLock
+{
+private:
+    inline static std::mutex mutex_;
+
+public:
+    PjInitLock()
+    {
+        std::lock_guard lk(mutex_);
+        pj_status_t status = pj_init();
+
+        if (status != PJ_SUCCESS) {
+            char errorMessage[PJ_ERR_MSG_SIZE];
+            pj_strerror(status, errorMessage, sizeof(errorMessage));
+            throw std::runtime_error(
+                fmt::format("pj_init failed: {}", errorMessage));
+        }
+    }
+
+    ~PjInitLock()
+    {
+        std::lock_guard lk(mutex_);
+        pj_shutdown();
+    }
+};
+
+}
diff --git a/src/ice_transport.cpp b/src/ice_transport.cpp
index d9beef8..1edf00c 100644
--- a/src/ice_transport.cpp
+++ b/src/ice_transport.cpp
@@ -1799,7 +1799,12 @@
 //==============================================================================
 
 IceTransportFactory::IceTransportFactory(const std::shared_ptr<Logger>& logger)
-    : cp_(new pj_caching_pool(),
+    : pjInitLock_()
+    // Warning: pj_caching_pool_destroy will segfault if it's called before
+    // pj_caching_pool_init. Hence, any member which appears in the initializer
+    // list and whose constructor can fail (such as pjInitLock_) must be constructed
+    // before cp_ (which means it must be declared before cp_ in the class definition).
+    , cp_(new pj_caching_pool(),
           [](pj_caching_pool* p) {
               pj_caching_pool_destroy(p);
               delete p;
diff --git a/src/turn/turn_transport.cpp b/src/turn/turn_transport.cpp
index 3ed4015..75525ff 100644
--- a/src/turn/turn_transport.cpp
+++ b/src/turn/turn_transport.cpp
@@ -147,7 +147,8 @@
 }
 
 TurnTransport::TurnTransport(const TurnTransportParams& params, std::function<void(bool)>&& cb, const std::shared_ptr<Logger>& logger)
-    : pimpl_ {new Impl(std::move(cb), logger)}
+    : pjInitLock_()
+    , pimpl_ {new Impl(std::move(cb), logger)}
 {
     auto server = params.server;
     if (!server.getPort())
diff --git a/src/turn/turn_transport.h b/src/turn/turn_transport.h
index b872454..37626b8 100644
--- a/src/turn/turn_transport.h
+++ b/src/turn/turn_transport.h
@@ -17,6 +17,7 @@
 #pragma once
 
 #include "ip_utils.h"
+#include "pj_init_lock.h"
 #include "turn_params.h"
 
 #include <opendht/logger.h>
@@ -48,6 +49,7 @@
 
 private:
     TurnTransport() = delete;
+    PjInitLock pjInitLock_;
     class Impl;
     std::unique_ptr<Impl> pimpl_;
 };