diff --git a/src/Makefile.test.include b/src/Makefile.test.include
--- a/src/Makefile.test.include
+++ b/src/Makefile.test.include
@@ -26,6 +26,7 @@
 # test_bitcoin binary #
 BITCOIN_TESTS =\
   test/scriptnum10.h \
+  test/activation_tests.cpp \
   test/addrman_tests.cpp \
   test/allocator_tests.cpp \
   test/amount_tests.cpp \
diff --git a/src/consensus/activation.h b/src/consensus/activation.h
--- a/src/consensus/activation.h
+++ b/src/consensus/activation.h
@@ -25,4 +25,7 @@
  */
 bool IsMagneticAnomalyEnabled(const Config &config, int64_t nMedianTimePast);
 
+/** Check if May 15th, 2019 protocol upgrade has activated. */
+bool IsGreatWallEnabled(const Config &config, const CBlockIndex *pindexPrev);
+
 #endif // BITCOIN_CONSENSUS_ACTIVATION_H
diff --git a/src/consensus/activation.cpp b/src/consensus/activation.cpp
--- a/src/consensus/activation.cpp
+++ b/src/consensus/activation.cpp
@@ -48,3 +48,15 @@
 
     return IsMagneticAnomalyEnabled(config, pindexPrev->GetMedianTimePast());
 }
+
+bool IsGreatWallEnabled(const Config &config, const CBlockIndex *pindexPrev) {
+
+    if (pindexPrev == nullptr) {
+        return false;
+    }
+
+    return pindexPrev->GetMedianTimePast() >=
+           gArgs.GetArg(
+               "-greatwallactivationtime",
+               config.GetChainParams().GetConsensus().greatWallActivationTime);
+}
diff --git a/src/test/CMakeLists.txt b/src/test/CMakeLists.txt
--- a/src/test/CMakeLists.txt
+++ b/src/test/CMakeLists.txt
@@ -44,6 +44,7 @@
 add_dependencies(check check-bitcoin)
 
 add_test_to_suite(bitcoin test_bitcoin
+	activation_tests.cpp
 	addrman_tests.cpp
 	allocator_tests.cpp
 	amount_tests.cpp
diff --git a/src/test/activation_tests.cpp b/src/test/activation_tests.cpp
new file mode 100644
--- /dev/null
+++ b/src/test/activation_tests.cpp
@@ -0,0 +1,35 @@
+// Copyright (c) 2019 The Bitcoin developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include "chain.h"
+#include "chainparams.h"
+#include "config.h"
+#include "consensus/activation.h"
+#include "test/test_bitcoin.h"
+
+#include <boost/test/unit_test.hpp>
+
+BOOST_FIXTURE_TEST_SUITE(activation_tests, BasicTestingSetup)
+
+BOOST_AUTO_TEST_CASE(isgreatwallenabled) {
+
+    DummyConfig cfg;
+    CBlockIndex prev;
+
+    const auto activation =
+        cfg.GetChainParams().GetConsensus().greatWallActivationTime;
+
+    BOOST_CHECK(!IsGreatWallEnabled(cfg, nullptr));
+
+    prev.nTime = activation - 1;
+    BOOST_CHECK(!IsGreatWallEnabled(cfg, &prev));
+
+    prev.nTime = activation;
+    BOOST_CHECK(IsGreatWallEnabled(cfg, &prev));
+
+    prev.nTime = activation + 1;
+    BOOST_CHECK(IsGreatWallEnabled(cfg, &prev));
+}
+
+BOOST_AUTO_TEST_SUITE_END()