diff --git a/cmake/local-libzmq/LocalLibzmq.cmake b/cmake/local-libzmq/LocalLibzmq.cmake
index c4fb722..48bb67a 100644
--- a/cmake/local-libzmq/LocalLibzmq.cmake
+++ b/cmake/local-libzmq/LocalLibzmq.cmake
@@ -1,7 +1,7 @@
 set(LIBZMQ_PREFIX ${CMAKE_BINARY_DIR}/libzmq)
-set(ZeroMQ_VERSION 4.3.3)
+set(ZeroMQ_VERSION 4.3.4)
 set(LIBZMQ_URL https://github.com/zeromq/libzmq/releases/download/v${ZeroMQ_VERSION}/zeromq-${ZeroMQ_VERSION}.tar.gz)
-set(LIBZMQ_HASH SHA512=4c18d784085179c5b1fcb753a93813095a12c8d34970f2e1bfca6499be6c9d67769c71c68b7ca54ff181b20390043170e89733c22f76ff1ea46494814f7095b1)
+set(LIBZMQ_HASH SHA512=e198ef9f82d392754caadd547537666d4fba0afd7d027749b3adae450516bcf284d241d4616cad3cb4ad9af8c10373d456de92dc6d115b037941659f141e7c0e)
 
 message(${LIBZMQ_URL})
 
diff --git a/tests/common.h b/tests/common.h
index 2798675..6cfe623 100644
--- a/tests/common.h
+++ b/tests/common.h
@@ -5,6 +5,16 @@
 
 using namespace oxenmq;
 
+// Apple's mutexes, thread scheduling, and IO handling are garbage and it shows up with lots of
+// spurious failures in this test suite (because it expects a system to not suck that badly), so we
+// multiply the time-sensitive bits by this factor as a hack to make the test suite work.
+constexpr int TIME_DILATION =
+#ifdef __APPLE__
+    5;
+#else
+    1;
+#endif
+
 static auto startup = std::chrono::steady_clock::now();
 
 /// Returns a localhost connection string to listen on.  It can be considered random, though in
@@ -30,7 +40,7 @@ inline void wait_for(Func f) {
     for (int i = 0; i < 20; i++) {
         if (f())
             break;
-        std::this_thread::sleep_for(10ms);
+        std::this_thread::sleep_for(10ms * TIME_DILATION);
     }
     auto lock = catch_lock();
     UNSCOPED_INFO("done waiting after " << (std::chrono::steady_clock::now() - start).count() << "ns");
@@ -43,7 +53,7 @@ inline void wait_for_conn(std::atomic<bool> &c) {
 }
 
 /// Waits enough time for us to receive a reply from a localhost remote.
-inline void reply_sleep() { std::this_thread::sleep_for(10ms); }
+inline void reply_sleep() { std::this_thread::sleep_for(10ms * TIME_DILATION); }
 
 inline OxenMQ::Logger get_logger(std::string prefix = "") {
     std::string me = "tests/common.h";
diff --git a/tests/test_commands.cpp b/tests/test_commands.cpp
index 606fed3..9dea29a 100644
--- a/tests/test_commands.cpp
+++ b/tests/test_commands.cpp
@@ -470,7 +470,7 @@ TEST_CASE("deferred replies", "[commands][send][deferred]") {
         std::string msg = m.data.empty() ? ""s : std::string{m.data.front()};
         std::thread t{[send=m.send_later(), msg=std::move(msg)] {
             { auto lock = catch_lock(); UNSCOPED_INFO("sleeping"); }
-            std::this_thread::sleep_for(50ms);
+            std::this_thread::sleep_for(50ms * TIME_DILATION);
             { auto lock = catch_lock(); UNSCOPED_INFO("sending"); }
             send.reply(msg);
         }};
@@ -516,7 +516,7 @@ TEST_CASE("deferred replies", "[commands][send][deferred]") {
         auto lock = catch_lock();
         REQUIRE( replies.size() == 0 ); // The server waits 50ms before sending, so we shouldn't have any reply yet
     }
-    std::this_thread::sleep_for(60ms); // We're at least 70ms in now so the 50ms-delayed server responses should have arrived
+    std::this_thread::sleep_for(60ms * TIME_DILATION); // We're at least 70ms in now so the 50ms-delayed server responses should have arrived
     {
         std::lock_guard lq{reply_mut};
         auto lock = catch_lock();
diff --git a/tests/test_connect.cpp b/tests/test_connect.cpp
index 0b4b846..b6cf109 100644
--- a/tests/test_connect.cpp
+++ b/tests/test_connect.cpp
@@ -279,7 +279,7 @@ TEST_CASE("SN disconnections", "[connect][disconnect]") {
     lmq[2]->send(pubkey[1], "sn.hi");
     lmq[1]->send(pubkey[0], "BYE");
     lmq[0]->send(pubkey[2], "sn.hi");
-    std::this_thread::sleep_for(50ms);
+    std::this_thread::sleep_for(50ms * TIME_DILATION);
 
     auto lock = catch_lock();
     REQUIRE(his == 5);
diff --git a/tests/test_timer.cpp b/tests/test_timer.cpp
index 93df350..0d78470 100644
--- a/tests/test_timer.cpp
+++ b/tests/test_timer.cpp
@@ -15,9 +15,10 @@ TEST_CASE("timer test", "[timer][basic]") {
     auto start = std::chrono::steady_clock::now();
     wait_for([&] { return ticks.load() > 3; });
     {
+        auto elapsed_ms = std::chrono::duration_cast<std::chrono::milliseconds>(std::chrono::steady_clock::now() - start).count();
         auto lock = catch_lock();
         REQUIRE( ticks.load() > 3 );
-        REQUIRE( std::chrono::steady_clock::now() - start < 40ms );
+        REQUIRE( elapsed_ms < 50 * TIME_DILATION );
     }
 }
 
@@ -35,13 +36,13 @@ TEST_CASE("timer squelch", "[timer][squelch]") {
     // finishes, by which point we set `done` and so should get exactly 1 tick.
     auto timer = omq.add_timer([&] {
         if (first.exchange(false)) {
-            std::this_thread::sleep_for(30ms);
+            std::this_thread::sleep_for(30ms * TIME_DILATION);
             ticks++;
             done = true;
         } else if (!done) {
             ticks++;
         }
-    }, 5ms, true /* squelch */);
+    }, 5ms * TIME_DILATION, true /* squelch */);
     omq.start();
 
     wait_for([&] { return done.load(); });
@@ -58,7 +59,7 @@ TEST_CASE("timer squelch", "[timer][squelch]") {
     std::atomic<int> ticks2 = 0;
     auto timer2 = omq.add_timer([&] {
         if (first2.exchange(false)) {
-            std::this_thread::sleep_for(30ms);
+            std::this_thread::sleep_for(40ms);
             done2 = true;
         } else if (!done2) {
             ticks2++;
@@ -82,13 +83,13 @@ TEST_CASE("timer cancel", "[timer][cancel]") {
     std::atomic<int> ticks = 0;
 
     // We set up *and cancel* this timer before omq starts, so it should never fire
-    auto notimer = omq.add_timer([&] { ticks += 1000; }, 5ms);
+    auto notimer = omq.add_timer([&] { ticks += 1000; }, 5ms * TIME_DILATION);
     omq.cancel_timer(notimer);
 
     TimerID timer = omq.add_timer([&] {
         if (++ticks == 3)
             omq.cancel_timer(timer);
-    }, 5ms);
+    }, 5ms * TIME_DILATION);
 
     omq.start();