diff --git a/test/Makefile.am b/test/Makefile.am
index 2223dfc..6cddc88 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -61,3 +61,8 @@
 source_time_SOURCES = source/time.cpp
 source_time_CPPFLAGS = $(gtest_cppflags)
 source_time_LDADD = $(gtest_ldadd)
+
+check_PROGRAMS += utility/timer
+utility_timer_SOURCES = utility/timer.cpp
+utility_timer_CPPFLAGS = $(gtest_cppflags)
+utility_timer_LDADD = $(gtest_ldadd)
diff --git a/test/utility/timer.cpp b/test/utility/timer.cpp
new file mode 100644
index 0000000..c919f7e
--- /dev/null
+++ b/test/utility/timer.cpp
@@ -0,0 +1,263 @@
+#include <chrono>
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+#include <memory>
+#include <sdeventplus/clock.hpp>
+#include <sdeventplus/event.hpp>
+#include <sdeventplus/test/sdevent.hpp>
+#include <sdeventplus/utility/timer.hpp>
+#include <stdexcept>
+#include <systemd/sd-event.h>
+
+namespace sdeventplus
+{
+namespace utility
+{
+namespace
+{
+
+constexpr ClockId testClock = ClockId::Monotonic;
+
+using std::chrono::microseconds;
+using std::chrono::milliseconds;
+using testing::DoAll;
+using testing::Return;
+using testing::SaveArg;
+using testing::SetArgPointee;
+using TestTimer = Timer<testClock>;
+
+ssize_t event_ref_times = 0;
+
+ACTION(EventRef)
+{
+    event_ref_times++;
+}
+
+ACTION(EventUnref)
+{
+    ASSERT_LT(0, event_ref_times);
+    event_ref_times--;
+}
+
+class TimerTest : public testing::Test
+{
+  protected:
+    testing::StrictMock<test::SdEventMock> mock;
+    sd_event* const expected_event = reinterpret_cast<sd_event*>(1234);
+    sd_event_source* const expected_source =
+        reinterpret_cast<sd_event_source*>(2345);
+    const milliseconds interval{134};
+    const milliseconds starting_time{10};
+    sd_event_time_handler_t handler = nullptr;
+    void* handler_userdata;
+    std::unique_ptr<TestTimer> timer;
+    std::function<void()> callback;
+
+    void expectNow(microseconds ret)
+    {
+        EXPECT_CALL(mock,
+                    sd_event_now(expected_event,
+                                 static_cast<clockid_t>(testClock), testing::_))
+            .WillOnce(DoAll(SetArgPointee<2>(ret.count()), Return(0)));
+    }
+
+    void expectSetTime(microseconds time)
+    {
+        EXPECT_CALL(mock,
+                    sd_event_source_set_time(expected_source, time.count()))
+            .WillOnce(Return(0));
+    }
+
+    void expectSetEnabled(source::Enabled enabled)
+    {
+        EXPECT_CALL(mock, sd_event_source_set_enabled(
+                              expected_source, static_cast<int>(enabled)))
+            .WillOnce(Return(0));
+    }
+
+    void expectGetEnabled(source::Enabled enabled)
+    {
+        EXPECT_CALL(mock,
+                    sd_event_source_get_enabled(expected_source, testing::_))
+            .WillOnce(
+                DoAll(SetArgPointee<1>(static_cast<int>(enabled)), Return(0)));
+    }
+
+    void SetUp()
+    {
+        EXPECT_CALL(mock, sd_event_ref(expected_event))
+            .WillRepeatedly(DoAll(EventRef(), Return(expected_event)));
+        EXPECT_CALL(mock, sd_event_unref(expected_event))
+            .WillRepeatedly(DoAll(EventUnref(), Return(nullptr)));
+        Event event(expected_event, &mock);
+
+        auto runCallback = [&]() {
+            if (callback)
+            {
+                callback();
+            }
+        };
+        expectNow(starting_time);
+        EXPECT_CALL(mock, sd_event_add_time(
+                              expected_event, testing::_,
+                              static_cast<clockid_t>(testClock),
+                              microseconds(starting_time + interval).count(),
+                              1000, testing::_, nullptr))
+            .WillOnce(DoAll(SetArgPointee<1>(expected_source),
+                            SaveArg<5>(&handler), Return(0)));
+        EXPECT_CALL(mock,
+                    sd_event_source_set_userdata(expected_source, testing::_))
+            .WillOnce(DoAll(SaveArg<1>(&handler_userdata), Return(nullptr)));
+        // Timer always enables the source to keep ticking
+        expectSetEnabled(source::Enabled::On);
+        timer = std::make_unique<TestTimer>(event, runCallback, interval);
+    }
+
+    void TearDown()
+    {
+        expectSetEnabled(source::Enabled::Off);
+        EXPECT_CALL(mock, sd_event_source_unref(expected_source))
+            .WillOnce(Return(nullptr));
+        timer.reset();
+        EXPECT_EQ(0, event_ref_times);
+    }
+};
+
+TEST_F(TimerTest, NewTimer)
+{
+    EXPECT_FALSE(timer->hasExpired());
+    EXPECT_EQ(interval, timer->getInterval());
+}
+
+TEST_F(TimerTest, IsEnabled)
+{
+    expectGetEnabled(source::Enabled::On);
+    EXPECT_TRUE(timer->isEnabled());
+    expectGetEnabled(source::Enabled::Off);
+    EXPECT_FALSE(timer->isEnabled());
+}
+
+TEST_F(TimerTest, GetRemainingDisabled)
+{
+    expectGetEnabled(source::Enabled::Off);
+    EXPECT_THROW(timer->getRemaining(), std::runtime_error);
+}
+
+TEST_F(TimerTest, GetRemainingNegative)
+{
+    milliseconds now(675), end(453);
+    expectGetEnabled(source::Enabled::On);
+    EXPECT_CALL(mock, sd_event_source_get_time(expected_source, testing::_))
+        .WillOnce(
+            DoAll(SetArgPointee<1>(microseconds(end).count()), Return(0)));
+    expectNow(now);
+    EXPECT_EQ(milliseconds(0), timer->getRemaining());
+}
+
+TEST_F(TimerTest, GetRemainingPositive)
+{
+    milliseconds now(453), end(675);
+    expectGetEnabled(source::Enabled::On);
+    EXPECT_CALL(mock, sd_event_source_get_time(expected_source, testing::_))
+        .WillOnce(
+            DoAll(SetArgPointee<1>(microseconds(end).count()), Return(0)));
+    expectNow(now);
+    EXPECT_EQ(end - now, timer->getRemaining());
+}
+
+TEST_F(TimerTest, SetEnabled)
+{
+    expectSetEnabled(source::Enabled::On);
+    timer->setEnabled(true);
+    EXPECT_FALSE(timer->hasExpired());
+    // Value should always be passed through regardless of current state
+    expectSetEnabled(source::Enabled::On);
+    timer->setEnabled(true);
+    EXPECT_FALSE(timer->hasExpired());
+
+    expectSetEnabled(source::Enabled::Off);
+    timer->setEnabled(false);
+    EXPECT_FALSE(timer->hasExpired());
+    // Value should always be passed through regardless of current state
+    expectSetEnabled(source::Enabled::Off);
+    timer->setEnabled(false);
+    EXPECT_FALSE(timer->hasExpired());
+}
+
+TEST_F(TimerTest, SetRemaining)
+{
+    const milliseconds now(90), remaining(30);
+    expectNow(now);
+    expectSetTime(now + remaining);
+    timer->setRemaining(remaining);
+    EXPECT_EQ(interval, timer->getInterval());
+    EXPECT_FALSE(timer->hasExpired());
+}
+
+TEST_F(TimerTest, ResetRemaining)
+{
+    const milliseconds now(90);
+    expectNow(now);
+    expectSetTime(now + interval);
+    timer->resetRemaining();
+    EXPECT_EQ(interval, timer->getInterval());
+    EXPECT_FALSE(timer->hasExpired());
+}
+
+TEST_F(TimerTest, SetInterval)
+{
+    const milliseconds new_interval(40);
+    timer->setInterval(new_interval);
+    EXPECT_EQ(new_interval, timer->getInterval());
+    EXPECT_FALSE(timer->hasExpired());
+}
+
+TEST_F(TimerTest, SetValuesExpiredTimer)
+{
+    const milliseconds new_time(90);
+    expectNow(new_time);
+    expectSetTime(new_time + interval);
+    EXPECT_EQ(0, handler(nullptr, 0, handler_userdata));
+    EXPECT_TRUE(timer->hasExpired());
+    EXPECT_EQ(interval, timer->getInterval());
+
+    // Timer should remain expired unless clearExpired() or reset()
+    expectSetEnabled(source::Enabled::On);
+    timer->setEnabled(true);
+    EXPECT_TRUE(timer->hasExpired());
+    expectNow(milliseconds(20));
+    expectSetTime(milliseconds(50));
+    timer->setRemaining(milliseconds(30));
+    EXPECT_TRUE(timer->hasExpired());
+    timer->setInterval(milliseconds(10));
+    EXPECT_TRUE(timer->hasExpired());
+    expectNow(milliseconds(20));
+    expectSetTime(milliseconds(30));
+    timer->resetRemaining();
+    EXPECT_TRUE(timer->hasExpired());
+
+    timer->clearExpired();
+    EXPECT_FALSE(timer->hasExpired());
+}
+
+TEST_F(TimerTest, Restart)
+{
+    const milliseconds new_time(90);
+    expectNow(new_time);
+    expectSetTime(new_time + interval);
+    EXPECT_EQ(0, handler(nullptr, 0, handler_userdata));
+    EXPECT_TRUE(timer->hasExpired());
+    EXPECT_EQ(interval, timer->getInterval());
+
+    const milliseconds new_interval(471);
+    expectNow(starting_time);
+    expectSetTime(starting_time + new_interval);
+    expectSetEnabled(source::Enabled::On);
+    timer->restart(new_interval);
+    EXPECT_FALSE(timer->hasExpired());
+    EXPECT_EQ(new_interval, timer->getInterval());
+}
+
+} // namespace
+} // namespace utility
+} // namespace sdeventplus