diff --git a/tools/lammps-gui/imageviewer.cpp b/tools/lammps-gui/imageviewer.cpp
index b1e2ecd787..4a7ac32c7c 100644
--- a/tools/lammps-gui/imageviewer.cpp
+++ b/tools/lammps-gui/imageviewer.cpp
@@ -190,6 +190,7 @@ ImageViewer::ImageViewer(const QString &fileName, LammpsWrapper *_lammps, QWidge
     mainLayout->addLayout(menuLayout);
     mainLayout->addWidget(scrollArea);
     mainLayout->addWidget(buttonBox);
+    setWindowIcon(QIcon(":/lammps-icon-128x128.png"));
     setWindowTitle(QString("Image Viewer: ") + QFileInfo(fileName).fileName());
     createActions();
 
diff --git a/tools/lammps-gui/lammpsgui.cpp b/tools/lammps-gui/lammpsgui.cpp
index d4f11d6019..7966db61af 100644
--- a/tools/lammps-gui/lammpsgui.cpp
+++ b/tools/lammps-gui/lammpsgui.cpp
@@ -1111,6 +1111,7 @@ void LammpsGui::about()
 
     QMessageBox msg;
     msg.setWindowTitle("About LAMMPS");
+    msg.setWindowIcon(QIcon(":/lammps-icon-128x128.png"));
     msg.setText(version.c_str());
     msg.setInformativeText(info.c_str());
     msg.setIconPixmap(QPixmap(":/lammps-icon-128x128.png").scaled(64, 64));
@@ -1130,6 +1131,7 @@ void LammpsGui::help()
 {
     QMessageBox msg;
     msg.setWindowTitle("LAMMPS-GUI Quick Help");
+    msg.setWindowIcon(QIcon(":/lammps-icon-128x128.png"));
     msg.setText("<div>This is LAMMPS-GUI version " LAMMPS_GUI_VERSION "</div>");
     msg.setInformativeText("<p>LAMMPS GUI is a graphical text editor that is linked to the LAMMPS "
                            "library and thus can run LAMMPS directly using the contents of the "
diff --git a/tools/lammps-gui/preferences.cpp b/tools/lammps-gui/preferences.cpp
index eb8d0fc8e2..91ecd191d4 100644
--- a/tools/lammps-gui/preferences.cpp
+++ b/tools/lammps-gui/preferences.cpp
@@ -78,6 +78,7 @@ Preferences::Preferences(LammpsWrapper *_lammps, QWidget *parent) :
     layout->addWidget(tabWidget);
     layout->addWidget(buttonBox);
     setLayout(layout);
+    setWindowIcon(QIcon(":/lammps-icon-128x128.png"));
     setWindowTitle("LAMMPS-GUI - Preferences");
     resize(500, 400);
 }
diff --git a/tools/lammps-gui/setvariables.cpp b/tools/lammps-gui/setvariables.cpp
index a63832fc57..fbbacb70bd 100644
--- a/tools/lammps-gui/setvariables.cpp
+++ b/tools/lammps-gui/setvariables.cpp
@@ -55,6 +55,7 @@ SetVariables::SetVariables(QList<QPair<QString, QString>> &_vars, QWidget *paren
 
     layout->addWidget(buttonBox);
     setLayout(layout);
+    setWindowIcon(QIcon(":/lammps-icon-128x128.png"));
     setWindowTitle("LAMMPS-GUI - Set Variables");
     resize(300, 200);
 }
diff --git a/tools/lammps-gui/slideshow.cpp b/tools/lammps-gui/slideshow.cpp
index d93b6fd052..418d2214ae 100644
--- a/tools/lammps-gui/slideshow.cpp
+++ b/tools/lammps-gui/slideshow.cpp
@@ -104,6 +104,7 @@ SlideShow::SlideShow(const QString &fileName, QWidget *parent) :
     mainLayout->addWidget(imageLabel);
     mainLayout->addLayout(navLayout);
     mainLayout->addWidget(buttonBox);
+    setWindowIcon(QIcon(":/lammps-icon-128x128.png"));
     setWindowTitle(QString("LAMMPS-GUI - Slide Show: ") + QFileInfo(fileName).fileName());
 
     imagefiles.clear();