diff --git a/doc/mkdwarfs.md b/doc/mkdwarfs.md
index bb07f581..d610a3b5 100644
--- a/doc/mkdwarfs.md
+++ b/doc/mkdwarfs.md
@@ -255,10 +255,14 @@ Most other options are concerned with compression tuning:
   size of the file system. If the input only has a single group already,
   setting this won't make any difference.
 
-- `--set-time=`*time*|`now`:
+- `--set-time=now`|*iso-8601-string*|*unix-timestamp*:
   Set the time stamps for all entities to this value. This can significantly
-  reduce the size of the file system. You can pass either a unix time stamp
-  or `now`.
+  reduce the size of the file system. You can pass the string `now` for the
+  current time, an ISO 8601 string, or a unix timestamp (seconds since epoch).
+  The ISO 8601 string supports a space character instead of the `T` between
+  date and time and supports dashes as separators. Seconds or the full time
+  part may be omitted as long as this doesn't turn the whole string into a
+  single number (i.e. `2008-03-17` is supported, but `20080317` is not).
 
 - `--keep-all-times`:
   As of release 0.3.0, by default, `mkdwarfs` will only save the contents of
diff --git a/src/mkdwarfs_main.cpp b/src/mkdwarfs_main.cpp
index cd0afdf7..b61707e7 100644
--- a/src/mkdwarfs_main.cpp
+++ b/src/mkdwarfs_main.cpp
@@ -934,9 +934,15 @@ int mkdwarfs_main(int argc, sys_char** argv, iolayer const& iol) {
     } else if (auto val = folly::tryTo<uint64_t>(timestamp)) {
       options.timestamp = *val;
     } else {
-      iol.err << "error: argument for option '--set-time' must be numeric or "
-                 "`now`\n";
-      return 1;
+      try {
+        auto tp = parse_time_point(timestamp);
+        options.timestamp = std::chrono::duration_cast<std::chrono::seconds>(
+                                tp.time_since_epoch())
+                                .count();
+      } catch (std::exception const& e) {
+        iol.err << "error: " << e.what() << "\n";
+        return 1;
+      }
     }
   }
 
diff --git a/test/tool_main_test.cpp b/test/tool_main_test.cpp
index 8facc66e..5dca0e5e 100644
--- a/test/tool_main_test.cpp
+++ b/test/tool_main_test.cpp
@@ -111,6 +111,10 @@ class mkdwarfs_tester {
     return mkdwarfs_main(args, iol.get());
   }
 
+  int run(std::initializer_list<std::string> args) {
+    return run(std::vector<std::string>(args));
+  }
+
   int run(std::string args) { return run(test::parse_args(args)); }
 
   filesystem_v2 fs_from_data(std::string data) {
@@ -126,6 +130,9 @@ class mkdwarfs_tester {
     return fs_from_data(std::move(fsimage.value()));
   }
 
+  std::string out() const { return iol.out(); }
+  std::string err() const { return iol.err(); }
+
   std::shared_ptr<test::test_file_access> fa;
   std::shared_ptr<test::os_access_mock> os;
   test::test_iolayer iol;
@@ -471,8 +478,8 @@ TEST(mkdwarfs_test, set_time_now) {
   auto t1 =
       std::chrono::system_clock::to_time_t(std::chrono::system_clock::now());
 
-  EXPECT_EQ(reg.size(), 11);
-  EXPECT_EQ(opt.size(), 1);
+  ASSERT_EQ(reg.size(), 11);
+  ASSERT_EQ(opt.size(), 1);
 
   EXPECT_GE(*opt.begin(), t0);
   EXPECT_LE(*opt.begin(), t1);
@@ -488,7 +495,29 @@ TEST(mkdwarfs_test, set_time_epoch) {
   auto opt = get_all_fs_times(*optfs);
 
   EXPECT_EQ(reg.size(), 11);
-  EXPECT_EQ(opt.size(), 1);
+  ASSERT_EQ(opt.size(), 1);
 
   EXPECT_EQ(*opt.begin(), 100000001);
 }
+
+TEST(mkdwarfs_test, set_time_epoch_string) {
+  using namespace std::chrono_literals;
+  using std::chrono::sys_days;
+
+  auto optfs = build_with_args({"--set-time", "2020-01-01 01:02"});
+  ASSERT_TRUE(optfs);
+  auto opt = get_all_fs_times(*optfs);
+
+  ASSERT_EQ(opt.size(), 1);
+
+  EXPECT_EQ(*opt.begin(),
+            std::chrono::duration_cast<std::chrono::seconds>(
+                (sys_days{2020y / 1 / 1} + 1h + 2min).time_since_epoch())
+                .count());
+}
+
+TEST(mkdwarfs_test, set_time_error) {
+  auto t = mkdwarfs_tester::create_empty();
+  EXPECT_NE(0, t.run({"-i", "/", "-o", "-", "--set-time=InVaLiD"}));
+  EXPECT_THAT(t.err(), ::testing::HasSubstr("cannot parse time point"));
+}