diff --git a/src/network/access/qnetworkrequest.cpp b/src/network/access/qnetworkrequest.cpp
index 94e2b437b3..558e015ae4 100644
--- a/src/network/access/qnetworkrequest.cpp
+++ b/src/network/access/qnetworkrequest.cpp
@@ -919,6 +919,7 @@ QNetworkHeadersPrivate::RawHeadersList QNetworkHeadersPrivate::allRawHeaders() c
 QList<QByteArray> QNetworkHeadersPrivate::rawHeadersKeys() const
 {
     QList<QByteArray> result;
+    result.reserve(rawHeaders.size());
     RawHeadersList::ConstIterator it = rawHeaders.constBegin(),
                                  end = rawHeaders.constEnd();
     for ( ; it != end; ++it)
diff --git a/src/network/kernel/qnetworkinterface.cpp b/src/network/kernel/qnetworkinterface.cpp
index 8d891733ac..2fbbf56e0f 100644
--- a/src/network/kernel/qnetworkinterface.cpp
+++ b/src/network/kernel/qnetworkinterface.cpp
@@ -108,6 +108,7 @@ QList<QSharedDataPointer<QNetworkInterfacePrivate> > QNetworkInterfaceManager::a
 {
     QList<QNetworkInterfacePrivate *> list = postProcess(scan());
     QList<QSharedDataPointer<QNetworkInterfacePrivate> > result;
+    result.reserve(list.size());
 
     foreach (QNetworkInterfacePrivate *ptr, list)
         result << QSharedDataPointer<QNetworkInterfacePrivate>(ptr);
@@ -549,6 +550,7 @@ QList<QNetworkInterface> QNetworkInterface::allInterfaces()
 {
     QList<QSharedDataPointer<QNetworkInterfacePrivate> > privs = manager()->allInterfaces();
     QList<QNetworkInterface> result;
+    result.reserve(privs.size());
     foreach (const QSharedDataPointer<QNetworkInterfacePrivate> &p, privs) {
         QNetworkInterface item;
         item.d = p;
diff --git a/src/network/ssl/qsslcertificate_openssl.cpp b/src/network/ssl/qsslcertificate_openssl.cpp
index ad88ea5d56..3324587821 100644
--- a/src/network/ssl/qsslcertificate_openssl.cpp
+++ b/src/network/ssl/qsslcertificate_openssl.cpp
@@ -464,8 +464,9 @@ QList<QSslCertificateExtension> QSslCertificate::extensions() const
         return result;
 
     int count = q_X509_get_ext_count(d->x509);
+    result.reserve(count);
 
-    for (int i=0; i < count; i++) {
+    for (int i = 0; i < count; i++) {
         X509_EXTENSION *ext = q_X509_get_ext(d->x509, i);
         result << QSslCertificatePrivate::convertExtension(ext);
     }
diff --git a/src/network/ssl/qsslsocket_openssl.cpp b/src/network/ssl/qsslsocket_openssl.cpp
index 436588afc5..55f0f3dd04 100644
--- a/src/network/ssl/qsslsocket_openssl.cpp
+++ b/src/network/ssl/qsslsocket_openssl.cpp
@@ -1199,7 +1199,9 @@ bool QSslSocketBackendPrivate::startHandshake()
     }
 
     // Translate errors from the error list into QSslErrors.
-    for (int i = 0; i < errorList.size(); ++i) {
+    const int numErrors = errorList.size();
+    errors.reserve(errors.size() + numErrors);
+    for (int i = 0; i < numErrors; ++i) {
         const QPair<int, int> &errorAndDepth = errorList.at(i);
         int err = errorAndDepth.first;
         int depth = errorAndDepth.second;
@@ -1761,7 +1763,9 @@ QList<QSslError> QSslSocketBackendPrivate::verify(const QList<QSslCertificate> &
     }
 
     // Translate errors from the error list into QSslErrors.
-    for (int i = 0; i < errorList.size(); ++i) {
+    const int numErrors = errorList.size();
+    errors.reserve(errors.size() + numErrors);
+    for (int i = 0; i < numErrors; ++i) {
         const QPair<int, int> &errorAndDepth = errorList.at(i);
         int err = errorAndDepth.first;
         int depth = errorAndDepth.second;