diff --git a/gnu/packages/patches/qtbase-use-TZDIR.patch b/gnu/packages/patches/qtbase-use-TZDIR.patch
index b6c377b133c..98bf7493e9f 100644
--- a/gnu/packages/patches/qtbase-use-TZDIR.patch
+++ b/gnu/packages/patches/qtbase-use-TZDIR.patch
@@ -1,39 +1,141 @@
-Use $TZDIR to search for time-zone data. Thus avoid depending on package
-"tzdata", which often introduces changes with near-immediate effects, so it's
-important to be able to update it fast.
+From 1075606f8b2f9e153c82f8e50cbd69cea9c72e87 Mon Sep 17 00:00:00 2001
+From: Edward Welbourne <edward.welbourne@qt.io>
+Date: Mon, 11 Sep 2023 11:41:39 +0200
+Subject: [PATCH] Support the TZDIR environment variable
 
-Based on a patch fron NixOS.
-===================================================================
---- qtbase-opensource-src-5.14.2.orig/src/corelib/time/qtimezoneprivate_tz.cpp
-+++ qtbase-opensource-src-5.15.2/src/corelib/time/qtimezoneprivate_tz.cpp
-@@ -70,7 +70,11 @@
- // Parse zone.tab table, assume lists all installed zones, if not will need to read directories
+On Linux / glibc, this overrides the default system location for the
+zone info. So check for files there first. Break out a function to
+manage the trying of (now three) zoneinfo directories when opening a
+file by name relative to there.
+
+Pick-to: 6.6 6.5
+Task-number: QTBUG-116017
+Change-Id: I1f97107aabd9015c0a5543639870f1d70654ca67
+---
+* Rebased on top of v6.5.2.
+
+ src/corelib/time/qtimezoneprivate_tz.cpp | 73 ++++++++++++++++--------
+ 1 file changed, 49 insertions(+), 24 deletions(-)
+
+diff --git a/src/corelib/time/qtimezoneprivate_tz.cpp b/src/corelib/time/qtimezoneprivate_tz.cpp
+index 067191d816..a8b2fc894e 100644
+--- a/src/corelib/time/qtimezoneprivate_tz.cpp
++++ b/src/corelib/time/qtimezoneprivate_tz.cpp
+@@ -51,17 +51,41 @@ typedef QHash<QByteArray, QTzTimeZone> QTzTimeZoneHash;
+ 
+ static bool isTzFile(const QString &name);
+ 
++// Open a named file under the zone info directory:
++static bool openZoneInfo(QString name, QFile *file)
++{
++    // At least on Linux / glibc (see man 3 tzset), $TZDIR overrides the system
++    // default location for zone info:
++    const QString tzdir = qEnvironmentVariable("TZDIR");
++    if (!tzdir.isEmpty()) {
++        file->setFileName(QDir(tzdir).filePath(name));
++        if (file->open(QIODevice::ReadOnly))
++            return true;
++    }
++    // Try modern system path first:
++    constexpr auto zoneShare = "/usr/share/zoneinfo/"_L1;
++    if (tzdir != zoneShare && tzdir != zoneShare.chopped(1)) {
++        file->setFileName(zoneShare + name);
++        if (file->open(QIODevice::ReadOnly))
++            return true;
++    }
++    // Fall back to legacy system path:
++    constexpr auto zoneLib = "/usr/lib/zoneinfo/"_L1;
++    if (tzdir != zoneLib && tzdir != zoneLib.chopped(1)) {
++        file->setFileName(zoneShare + name);
++        if (file->open(QIODevice::ReadOnly))
++            return true;
++    }
++    return false;
++}
++
+ // Parse zone.tab table for territory information, read directories to ensure we
+ // find all installed zones (many are omitted from zone.tab; even more from
+ // zone1970.tab).
  static QTzTimeZoneHash loadTzTimeZones()
  {
 -    QString path = QStringLiteral("/usr/share/zoneinfo/zone.tab");
-+    // Try TZDIR first, in case we're running on GuixSD.
-+    QString path = QFile::decodeName(qgetenv("TZDIR")) + QStringLiteral("/zone.tab");
-+    // Fallback to traditional paths in case we are not on GuixSD.
-+    if (!QFile::exists(path))
-+        path = QStringLiteral("/usr/share/zoneinfo/zone.tab");
-     if (!QFile::exists(path))
-         path = QStringLiteral("/usr/lib/zoneinfo/zone.tab");
+-    if (!QFile::exists(path))
+-        path = QStringLiteral("/usr/lib/zoneinfo/zone.tab");
+-
+-    QFile tzif(path);
+-    if (!tzif.open(QIODevice::ReadOnly))
++    QFile tzif;
++    if (!openZoneInfo("zone.tab"_L1, &tzif))
+         return QTzTimeZoneHash();
  
-@@ -645,6 +649,9 @@
+     QTzTimeZoneHash zonesHash;
+@@ -91,6 +115,7 @@ static QTzTimeZoneHash loadTzTimeZones()
+         }
+     }
+ 
++    const QString path = tzif.fileName();
+     const qsizetype cut = path.lastIndexOf(u'/');
+     Q_ASSERT(cut > 0);
+     const QDir zoneDir = QDir(path.first(cut));
+@@ -761,20 +786,13 @@ QTzTimeZoneCacheEntry QTzTimeZoneCache::findEntry(const QByteArray &ianaId)
+         tzif.setFileName(QStringLiteral("/etc/localtime"));
          if (!tzif.open(QIODevice::ReadOnly))
-             return;
-     } else {
-+      // Try TZDIR first, in case we're running on GuixSD.
-+      tzif.setFileName(QFile::decodeName(qgetenv("TZDIR")) + QStringLiteral("/") + QString::fromLocal8Bit(ianaId));
-+      if (!tzif.open(QIODevice::ReadOnly)) {
-         // Open named tz, try modern path first, if fails try legacy path
-         tzif.setFileName(QLatin1String("/usr/share/zoneinfo/") + QString::fromLocal8Bit(ianaId));
-         if (!tzif.open(QIODevice::ReadOnly)) {
-@@ -652,6 +659,7 @@
-             if (!tzif.open(QIODevice::ReadOnly))
-                 return;
+             return ret;
+-    } else {
+-        // Open named tz, try modern path first, if fails try legacy path
+-        tzif.setFileName("/usr/share/zoneinfo/"_L1 + QString::fromLocal8Bit(ianaId));
+-        if (!tzif.open(QIODevice::ReadOnly)) {
+-            tzif.setFileName("/usr/lib/zoneinfo/"_L1 + QString::fromLocal8Bit(ianaId));
+-            if (!tzif.open(QIODevice::ReadOnly)) {
+-                // ianaId may be a POSIX rule, taken from $TZ or /etc/TZ
+-                auto check = validatePosixRule(ianaId);
+-                if (check.isValid) {
+-                    ret.m_hasDst = check.hasDst;
+-                    ret.m_posixRule = ianaId;
+-                }
+-                return ret;
+-            }
++    } else if (!openZoneInfo(QString::fromLocal8Bit(ianaId), &tzif)) {
++        // ianaId may be a POSIX rule, taken from $TZ or /etc/TZ
++        auto check = validatePosixRule(ianaId);
++        if (check.isValid) {
++            ret.m_hasDst = check.hasDst;
++            ret.m_posixRule = ianaId;
++            return ret;
          }
-+      }
      }
  
-     QDataStream ds(&tzif);
+@@ -1317,7 +1335,8 @@ private:
+     {
+         // On most distros /etc/localtime is a symlink to a real file so extract
+         // name from the path
+-        const auto zoneinfo = "/zoneinfo/"_L1;
++        const QString tzdir = qEnvironmentVariable("TZDIR");
++        constexpr auto zoneinfo = "/zoneinfo/"_L1;
+         QString path = QStringLiteral("/etc/localtime");
+         long iteration = getSymloopMax();
+         // Symlink may point to another symlink etc. before being under zoneinfo/
+@@ -1325,9 +1344,15 @@ private:
+         // symlink, like America/Montreal pointing to America/Toronto
+         do {
+             path = QFile::symLinkTarget(path);
+-            int index = path.indexOf(zoneinfo);
+-            if (index >= 0) // Found zoneinfo file; extract zone name from path:
+-                return QStringView{ path }.mid(index + zoneinfo.size()).toUtf8();
++            // If it's a zoneinfo file, extract the zone name from its path:
++            int index = tzdir.isEmpty() ? -1 : path.indexOf(tzdir);
++            if (index >= 0) {
++                const auto tail = QStringView{ path }.sliced(index + tzdir.size()).toUtf8();
++                return tail.startsWith(u'/') ? tail.sliced(1) : tail;
++            }
++            index = path.indexOf(zoneinfo);
++            if (index >= 0)
++                return QStringView{ path }.sliced(index + zoneinfo.size()).toUtf8();
+         } while (!path.isEmpty() && --iteration > 0);
+ 
+         return QByteArray();
+
+base-commit: af457a9f0f7eb1a2a7d11f495da508faab91a442
+-- 
+2.41.0
+
diff --git a/gnu/packages/qt.scm b/gnu/packages/qt.scm
index 8324beef6fc..d6255248c2a 100644
--- a/gnu/packages/qt.scm
+++ b/gnu/packages/qt.scm
@@ -747,7 +747,8 @@ (define-public qtbase
               (assoc-ref %standard-phases 'configure))
             (delete 'check)             ;move after patch-prl-files
             (add-after 'patch-prl-files 'check
-              (lambda* (#:key tests? parallel-tests? #:allow-other-keys)
+              (lambda* (#:key tests? parallel-tests?
+                        native-inputs inputs #:allow-other-keys)
                 (when tests?
                   ;; The tests expect to find the modules provided by this
                   ;; package; extend the environment variables needed to do so.
@@ -770,6 +771,18 @@ (define-public qtbase
                   ;; /tree/src/testlib/qtestblacklist.cpp).
                   (setenv "QTEST_ENVIRONMENT" "linux ci 32bit")
                   (setenv "HOME" "/tmp") ;some tests require a writable HOME
+
+                  ;; Note: the search path specified for TZDIR is only
+                  ;; effective for users of the package, not while it's being
+                  ;; built.
+                  (setenv "TZDIR" (search-input-directory
+                                   (or native-inputs inputs) "share/zoneinfo"))
+
+                  ;; This is to avoid QTimeZone::systemTimeZone() returning
+                  ;; invalid QDate objects due to missing /etc/timezone or
+                  ;; /etc/localtime.
+                  (setenv "TZ" "Etc/UTC")
+
                   (invoke
                    "xvfb-run" "ctest" "--output-on-failure"
                    "-j" (if parallel-tests?
@@ -783,11 +796,6 @@ (define-public qtbase
                       ;; The 'tst_moc' test fails with "'fi.exists()' returned FALSE".
                       "tst_moc"
 
-                      ;; The 'tst_qdate' test fails because the current time
-                      ;; is reported as an invalid date (see:
-                      ;; https://bugreports.qt.io/browse/QTBUG-116017).
-                      "tst_qdate"
-
                       ;; The qgraphicsview and qopenglwidget tests fail with a
                       ;; segfault for unknown reasons (see:
                       ;; https://bugreports.qt.io/browse/QTBUG-116018).
@@ -826,14 +834,6 @@ (define-public qtbase
                       ;; The 'test_import_plugins' fails with "Could NOT find
                       ;; Qt6MockPlugins1".
                       "test_import_plugins"
-                      ;; The 'tst_QTimeZone::systemZone' validates the
-                      ;; currently set timezone and fails.
-                      "tst_qtimezone"
-                      ;; The 'tst_qdatetime' fails with:
-                      ;; FAIL!  : tst_QDateTime::offsetFromUtc() Compared values are not the same
-                      ;; Actual   (dt5.offsetFromUtc()): 0
-                      ;; Expected (46800)              : 46800
-                      "tst_qdatetime"
                       ;; The tst_QObjectRace::destroyRace is flaky (see:
                       ;; https://bugreports.qt.io/browse/QTBUG-103489).
                       "tst_qobjectrace"
@@ -910,7 +910,8 @@ (define-public qtbase
                     (("\\$\\$\\[QT_HOST_DATA/src\\]") archdata)))))))))
     (native-inputs
      (modify-inputs (package-native-inputs qtbase-5)
-       (prepend wayland-protocols
+       (prepend tzdata-for-tests
+                wayland-protocols
                 xvfb-run)))
     (inputs
      (modify-inputs (package-inputs qtbase-5)
