diff --git a/libtaskmanager/abstracttasksmodel.h b/libtaskmanager/abstracttasksmodel.h
--- a/libtaskmanager/abstracttasksmodel.h
+++ b/libtaskmanager/abstracttasksmodel.h
@@ -233,6 +233,19 @@
     virtual void requestVirtualDesktop(const QModelIndex &index, qint32 desktop) override;
 
     /**
+     * Request moving the task at the given index to the specified activities.
+     *
+     * This is meant for tasks that have an associated window, and may be
+     * a no-op when there is no window.
+     *
+     * This base implementation does nothing.
+     *
+     * @param index An index in this tasks model.
+     * @param activities The new list of activities.
+     **/
+    virtual void requestActivities(const QModelIndex &index, const QStringList &activities);
+
+    /**
      * Request informing the window manager of new geometry for a visual
      * delegate for the task at the given index. The geometry should be in
      * screen coordinates.
diff --git a/libtaskmanager/abstracttasksmodel.cpp b/libtaskmanager/abstracttasksmodel.cpp
--- a/libtaskmanager/abstracttasksmodel.cpp
+++ b/libtaskmanager/abstracttasksmodel.cpp
@@ -113,6 +113,12 @@
     Q_UNUSED(desktop)
 }
 
+void AbstractTasksModel::requestActivities(const QModelIndex &index, const QStringList &activities)
+{
+    Q_UNUSED(index)
+    Q_UNUSED(activities)
+}
+
 void AbstractTasksModel::requestPublishDelegateGeometry(const QModelIndex &index, const QRect &geometry, QObject *delegate)
 {
     Q_UNUSED(index)
diff --git a/libtaskmanager/abstracttasksmodeliface.h b/libtaskmanager/abstracttasksmodeliface.h
--- a/libtaskmanager/abstracttasksmodeliface.h
+++ b/libtaskmanager/abstracttasksmodeliface.h
@@ -160,6 +160,18 @@
     virtual void requestVirtualDesktop(const QModelIndex &index, qint32 desktop = -1) = 0;
 
     /**
+     * Request moving the task at the given index to the specified virtual
+     * activities.
+     *
+     * This is meant for tasks that have an associated window, and may be
+     * a no-op when there is no window.
+     *
+     * @param index An index in this tasks model.
+     * @param activities The new list of activities.
+     **/
+    virtual void requestActivities(const QModelIndex &index, const QStringList &activities) = 0;
+
+    /**
      * Request informing the window manager of new geometry for a visual
      * delegate for the task at the given index. The geometry should be in
      * screen coordinates.
diff --git a/libtaskmanager/activityinfo.h b/libtaskmanager/activityinfo.h
--- a/libtaskmanager/activityinfo.h
+++ b/libtaskmanager/activityinfo.h
@@ -72,7 +72,7 @@
      *
      * @returns the list of currently-running activities defined in the session.
      **/
-    QStringList runningActivities() const;
+    Q_INVOKABLE QStringList runningActivities() const;
 
     /**
      * The name of the activity of the given id.
diff --git a/libtaskmanager/concatenatetasksproxymodel.h b/libtaskmanager/concatenatetasksproxymodel.h
--- a/libtaskmanager/concatenatetasksproxymodel.h
+++ b/libtaskmanager/concatenatetasksproxymodel.h
@@ -165,6 +165,19 @@
     void requestVirtualDesktop(const QModelIndex &index, qint32 desktop);
 
     /**
+     * Request moving the task at the given index to the specified activities.
+     *
+     * This is meant for tasks that have an associated window, and may be
+     * a no-op when there is no window.
+     *
+     * This base implementation does nothing.
+     *
+     * @param index An index in this tasks model.
+     * @param activities The new list of activities.
+     **/
+    void requestActivities(const QModelIndex &index, const QStringList &activities);
+
+    /**
      * Request informing the window manager of new geometry for a visual
      * delegate for the task at the given index. The geometry should be in
      * screen coordinates.
diff --git a/libtaskmanager/concatenatetasksproxymodel.cpp b/libtaskmanager/concatenatetasksproxymodel.cpp
--- a/libtaskmanager/concatenatetasksproxymodel.cpp
+++ b/libtaskmanager/concatenatetasksproxymodel.cpp
@@ -223,6 +223,23 @@
     }
 }
 
+void ConcatenateTasksProxyModel::requestActivities(const QModelIndex &index, const QStringList &activities)
+{
+    if (!index.isValid() || index.model() != this) {
+        return;
+    }
+
+    const QModelIndex &sourceIndex = mapToSource(index);
+    const AbstractTasksModelIface *m = dynamic_cast<const AbstractTasksModelIface *>(sourceIndex.model());
+
+    if (m) {
+        // NOTE: KConcatenateRowsProxyModel offers no way to get a non-const pointer
+        // to one of the source models, so we have to go through a mapped index.
+        const_cast<AbstractTasksModelIface *>(m)->requestActivities(sourceIndex, activities);
+    }
+}
+
+
 void ConcatenateTasksProxyModel::requestPublishDelegateGeometry(const QModelIndex &index, const QRect &geometry, QObject *delegate)
 {
     if (!index.isValid() || index.model() != this) {
diff --git a/libtaskmanager/flattentaskgroupsproxymodel.h b/libtaskmanager/flattentaskgroupsproxymodel.h
--- a/libtaskmanager/flattentaskgroupsproxymodel.h
+++ b/libtaskmanager/flattentaskgroupsproxymodel.h
@@ -168,6 +168,17 @@
     void requestVirtualDesktop(const QModelIndex &index, qint32 desktop) override;
 
     /**
+     * Request moving the task at the given index to the specified activities.
+     *
+     * This is meant for tasks that have an associated window, and may be
+     * a no-op when there is no window.
+     *     *
+     * @param index An index in this tasks model.
+     * @param activities The new list of activities.
+     **/
+    void requestActivities(const QModelIndex &index, const QStringList &activities);
+
+    /**
      * Request informing the window manager of new geometry for a visual
      * delegate for the task at the given index. The geometry should be in
      * screen coordinates.
diff --git a/libtaskmanager/flattentaskgroupsproxymodel.cpp b/libtaskmanager/flattentaskgroupsproxymodel.cpp
--- a/libtaskmanager/flattentaskgroupsproxymodel.cpp
+++ b/libtaskmanager/flattentaskgroupsproxymodel.cpp
@@ -140,6 +140,13 @@
     }
 }
 
+void FlattenTaskGroupsProxyModel::requestActivities(const QModelIndex &index, const QStringList &activities)
+{
+    if (d->sourceTasksModel && index.isValid() && index.model() == this) {
+        d->sourceTasksModel->requestActivities(mapToSource(index), activities);
+    }
+}
+
 void FlattenTaskGroupsProxyModel::requestPublishDelegateGeometry(const QModelIndex &index, const QRect &geometry, QObject *delegate)
 {
     if (index.isValid() && index.model() == this) {
diff --git a/libtaskmanager/taskfilterproxymodel.h b/libtaskmanager/taskfilterproxymodel.h
--- a/libtaskmanager/taskfilterproxymodel.h
+++ b/libtaskmanager/taskfilterproxymodel.h
@@ -325,6 +325,19 @@
     void requestVirtualDesktop(const QModelIndex &index, qint32 desktop) override;
 
     /**
+     * Request moving the task at the given index to the specified activities.
+     *
+     * This is meant for tasks that have an associated window, and may be
+     * a no-op when there is no window.
+     *
+     * This base implementation does nothing.
+     *
+     * @param index An index in this tasks model.
+     * @param activities The new list of activities.
+     **/
+    void requestActivities(const QModelIndex &index, const QStringList &activities);
+
+    /**
      * Request informing the window manager of new geometry for a visual
      * delegate for the task at the given index. The geometry should be in
      * screen coordinates.
diff --git a/libtaskmanager/taskfilterproxymodel.cpp b/libtaskmanager/taskfilterproxymodel.cpp
--- a/libtaskmanager/taskfilterproxymodel.cpp
+++ b/libtaskmanager/taskfilterproxymodel.cpp
@@ -268,6 +268,13 @@
     }
 }
 
+void TaskFilterProxyModel::requestActivities(const QModelIndex &index, const QStringList &activities)
+{
+    if (d->sourceTasksModel && index.isValid() && index.model() == this) {
+        d->sourceTasksModel->requestActivities(mapToSource(index), activities);
+    }
+}
+
 void TaskFilterProxyModel::requestPublishDelegateGeometry(const QModelIndex &index, const QRect &geometry, QObject *delegate)
 {
     if (index.isValid() && index.model() == this) {
diff --git a/libtaskmanager/taskgroupingproxymodel.h b/libtaskmanager/taskgroupingproxymodel.h
--- a/libtaskmanager/taskgroupingproxymodel.h
+++ b/libtaskmanager/taskgroupingproxymodel.h
@@ -317,6 +317,19 @@
     void requestVirtualDesktop(const QModelIndex &index, qint32 desktop) override;
 
     /**
+     * Request moving the task at the given index to the specified activities.
+     *
+     * This is meant for tasks that have an associated window, and may be
+     * a no-op when there is no window.
+     *
+     * This base implementation does nothing.
+     *
+     * @param index An index in this tasks model.
+     * @param activities The new list of activities.
+     **/
+    virtual void requestActivities(const QModelIndex &index, const QStringList &activities);
+
+    /**
      * Request informing the window manager of new geometry for a visual
      * delegate for the task at the given index. The geometry should be in
      * screen coordinates.
diff --git a/libtaskmanager/taskgroupingproxymodel.cpp b/libtaskmanager/taskgroupingproxymodel.cpp
--- a/libtaskmanager/taskgroupingproxymodel.cpp
+++ b/libtaskmanager/taskgroupingproxymodel.cpp
@@ -1127,6 +1127,27 @@
     }
 }
 
+void TaskGroupingProxyModel::requestActivities(const QModelIndex &index, const QStringList &activities)
+{
+    if (!d->abstractTasksSourceModel || !index.isValid() || index.model() != this) {
+        return;
+    }
+
+    if (index.parent().isValid() || !d->isGroup(index.row())) {
+        d->abstractTasksSourceModel->requestActivities(mapToSource(index), activities);
+    } else {
+        const int row = index.row();
+
+        for (int i = (rowCount(index) - 1); i >= 1; --i) {
+            const QModelIndex &sourceChild = mapToSource(index.child(i, 0));
+            d->abstractTasksSourceModel->requestActivities(sourceChild, activities);
+        }
+
+        d->abstractTasksSourceModel->requestActivities(mapToSource(TaskGroupingProxyModel::index(row, 0)),
+            activities);
+    }
+}
+
 void TaskGroupingProxyModel::requestPublishDelegateGeometry(const QModelIndex &index, const QRect &geometry, QObject *delegate)
 {
     if (!d->abstractTasksSourceModel || !index.isValid() || index.model() != this) {
diff --git a/libtaskmanager/tasksmodel.h b/libtaskmanager/tasksmodel.h
--- a/libtaskmanager/tasksmodel.h
+++ b/libtaskmanager/tasksmodel.h
@@ -623,6 +623,19 @@
     Q_INVOKABLE void requestVirtualDesktop(const QModelIndex &index, qint32 desktop) override;
 
     /**
+     * Request moving the task at the given index to the specified activities.
+     *
+     * This is meant for tasks that have an associated window, and may be
+     * a no-op when there is no window.
+     *
+     * This base implementation does nothing.
+     *
+     * @param index An index in this tasks model.
+     * @param activities The new list of activities.
+     **/
+    Q_INVOKABLE virtual void requestActivities(const QModelIndex &index, const QStringList &activities);
+
+    /**
      * Request informing the window manager of new geometry for a visual
      * delegate for the task at the given index. The geometry should be in
      * screen coordinates.
diff --git a/libtaskmanager/tasksmodel.cpp b/libtaskmanager/tasksmodel.cpp
--- a/libtaskmanager/tasksmodel.cpp
+++ b/libtaskmanager/tasksmodel.cpp
@@ -1232,6 +1232,13 @@
     }
 }
 
+void TasksModel::requestActivities(const QModelIndex &index, const QStringList &activities)
+{
+    if (index.isValid() && index.model() == this) {
+        d->groupingProxyModel->requestActivities(mapToSource(index), activities);
+    }
+}
+
 void TasksModel::requestPublishDelegateGeometry(const QModelIndex &index, const QRect &geometry, QObject *delegate)
 {
     if (index.isValid() && index.model() == this) {
diff --git a/libtaskmanager/waylandtasksmodel.h b/libtaskmanager/waylandtasksmodel.h
--- a/libtaskmanager/waylandtasksmodel.h
+++ b/libtaskmanager/waylandtasksmodel.h
@@ -163,6 +163,16 @@
     void requestVirtualDesktop(const QModelIndex &index, qint32 desktop) override;
 
     /**
+     * Request moving the window at the given index to the specified activities
+     *
+     * FIXME: This currently does nothing as activities is not implementated in kwin/kwayland
+     *
+     * @param index An index in this window tasks model.
+     * @param desktop A virtual desktop number.
+     **/
+    void requestActivities(const QModelIndex &index, const QStringList &activities) override;
+
+    /**
      * Request informing the window manager of new geometry for a visual
      * delegate for the window at the given index. The geometry is retrieved
      * from the delegate object passed. Right now, QQuickItem is the only
diff --git a/libtaskmanager/waylandtasksmodel.cpp b/libtaskmanager/waylandtasksmodel.cpp
--- a/libtaskmanager/waylandtasksmodel.cpp
+++ b/libtaskmanager/waylandtasksmodel.cpp
@@ -462,6 +462,12 @@
     d->windows.at(index.row())->requestVirtualDesktop(desktop);
 }
 
+void WaylandTasksModel::requestActivities(const QModelIndex &index, const QStringList &activities)
+{
+    Q_UNUSED(index)
+    Q_UNUSED(activities)
+}
+
 void WaylandTasksModel::requestPublishDelegateGeometry(const QModelIndex &index, const QRect &geometry, QObject *delegate)
 {
     /*
diff --git a/libtaskmanager/xwindowtasksmodel.h b/libtaskmanager/xwindowtasksmodel.h
--- a/libtaskmanager/xwindowtasksmodel.h
+++ b/libtaskmanager/xwindowtasksmodel.h
@@ -177,6 +177,17 @@
     void requestVirtualDesktop(const QModelIndex &index, qint32 desktop) override;
 
     /**
+     * Request moving the task at the given index to the specified activities.
+     *
+     * This is meant for tasks that have an associated window, and may be
+     * a no-op when there is no window.
+     *     *
+     * @param index An index in this tasks model.
+     * @param activities The new list of activities.
+     **/
+    void requestActivities(const QModelIndex &index, const QStringList &activities) override;
+
+    /**
      * Request informing the window manager of new geometry for a visual
      * delegate for the window at the given index.
      *
diff --git a/libtaskmanager/xwindowtasksmodel.cpp b/libtaskmanager/xwindowtasksmodel.cpp
--- a/libtaskmanager/xwindowtasksmodel.cpp
+++ b/libtaskmanager/xwindowtasksmodel.cpp
@@ -1199,6 +1199,18 @@
     }
 }
 
+void XWindowTasksModel::requestActivities(const QModelIndex &index, const QStringList &activities)
+{
+    if (!index.isValid() || index.model() != this || index.row() < 0 || index.row() >= d->windows.count()) {
+        return;
+    }
+
+    const WId window = d->windows.at(index.row());
+
+    KWindowSystem::setOnActivities(window, activities);
+}
+
+
 void XWindowTasksModel::requestPublishDelegateGeometry(const QModelIndex &index, const QRect &geometry, QObject *delegate)
 {
     Q_UNUSED(delegate)