diff --git a/src/btop_input.cpp b/src/btop_input.cpp
index 28a9667..ff68d5e 100644
--- a/src/btop_input.cpp
+++ b/src/btop_input.cpp
@@ -346,6 +346,11 @@ namespace Input {
 					no_update = false;
 					Config::set("update_following", true);
 				}
+				else if (key == "E" and Config::getB("proc_tree")) {
+					atomic_wait(Runner::active);
+					Proc::collapse_all = 1;
+					no_update = false;
+				}
 				else if (is_in(key, "u")) {
 					Config::flip("pause_proc_list");
 				}
diff --git a/src/btop_menu.cpp b/src/btop_menu.cpp
index fbaadf3..36e3958 100644
--- a/src/btop_menu.cpp
+++ b/src/btop_menu.cpp
@@ -205,6 +205,7 @@ namespace Menu {
 		{"c", "Toggle per-core cpu usage of processes."},
 		{"r", "Reverse sorting order in processes box."},
 		{"e", "Toggle processes tree view."},
+			{"E", "Collapse/expand all processes in tree view."},
 		{"%", "Toggles memory display mode in processes box."},
 		{"Selected +, -", "Expand/collapse the selected process in tree view."},
 		{"Selected t", "Terminate selected process with SIGTERM - 15."},
diff --git a/src/btop_shared.hpp b/src/btop_shared.hpp
index 96f4de3..00020b1 100644
--- a/src/btop_shared.hpp
+++ b/src/btop_shared.hpp
@@ -360,7 +360,7 @@ namespace Proc {
 	extern bool shown, redraw;
 	extern int select_max;
 	extern atomic<int> detailed_pid;
-	extern int selected_pid, start, selected, collapse, expand, filter_found, selected_depth, toggle_children;
+	extern int selected_pid, start, selected, collapse, expand, filter_found, selected_depth, toggle_children, collapse_all;
 	extern int scroll_pos;
 	extern string selected_name;
 	extern atomic<bool> resized;
diff --git a/src/freebsd/btop_collect.cpp b/src/freebsd/btop_collect.cpp
index 17f916f..f4318b2 100644
--- a/src/freebsd/btop_collect.cpp
+++ b/src/freebsd/btop_collect.cpp
@@ -1007,7 +1007,7 @@ namespace Proc {
 	fs::file_time_type passwd_time;
 
 	uint64_t cputimes;
-	int collapse = -1, expand = -1, toggle_children = -1;
+	int collapse = -1, expand = -1, toggle_children = -1, collapse_all = -1;
 	uint64_t old_cputimes = 0;
 	atomic<int> numpids = 0;
 	int filter_found = 0;
@@ -1301,6 +1301,21 @@ namespace Proc {
 				}
 				collapse = expand = -1;
 			}
+
+			if (collapse_all != -1) {
+				//? If any parent process is currently expanded, collapse all; otherwise expand all
+				std::unordered_set<size_t> parent_pids;
+				for (const auto& p : current_procs)
+					parent_pids.insert(static_cast<size_t>(p.ppid));
+				const bool do_collapse = rng::any_of(current_procs, [&parent_pids](const proc_info& p) {
+					return parent_pids.contains(p.pid) and not p.collapsed;
+				});
+				for (auto& p : current_procs)
+					p.collapsed = do_collapse;
+				collapse_all = -1;
+				if (Config::ints.at("proc_selected") > 0) locate_selection = true;
+			}
+
 			if (should_filter or not filter.empty()) filter_found = 0;
 
 			vector<tree_proc> tree_procs;
diff --git a/src/linux/btop_collect.cpp b/src/linux/btop_collect.cpp
index 454f8e8..be4526d 100644
--- a/src/linux/btop_collect.cpp
+++ b/src/linux/btop_collect.cpp
@@ -2879,7 +2879,7 @@ namespace Proc {
 	fs::file_time_type passwd_time;
 
 	uint64_t cputimes;
-	int collapse = -1, expand = -1, toggle_children = -1;
+	int collapse = -1, expand = -1, toggle_children = -1, collapse_all = -1;
 	uint64_t old_cputimes{};
 	atomic<int> numpids{};
 	int filter_found{};
@@ -3354,6 +3354,21 @@ namespace Proc {
 				}
 				collapse = expand = -1;
 			}
+
+			if (collapse_all != -1) {
+				//? If any parent process is currently expanded, collapse all; otherwise expand all
+				std::unordered_set<size_t> parent_pids;
+				for (const auto& p : current_procs)
+					parent_pids.insert(static_cast<size_t>(p.ppid));
+				const bool do_collapse = rng::any_of(current_procs, [&parent_pids](const proc_info& p) {
+					return parent_pids.contains(p.pid) and not p.collapsed;
+				});
+				for (auto& p : current_procs)
+					p.collapsed = do_collapse;
+				collapse_all = -1;
+				if (Config::ints.at("proc_selected") > 0) locate_selection = true;
+			}
+
 			if (should_filter or not filter.empty()) filter_found = 0;
 
 			vector<tree_proc> tree_procs;
diff --git a/src/netbsd/btop_collect.cpp b/src/netbsd/btop_collect.cpp
index 9f56899..875cdc5 100644
--- a/src/netbsd/btop_collect.cpp
+++ b/src/netbsd/btop_collect.cpp
@@ -1100,7 +1100,7 @@ namespace Proc {
 	fs::file_time_type passwd_time;
 
 	uint64_t cputimes;
-	int collapse = -1, expand = -1, toggle_children = -1;
+	int collapse = -1, expand = -1, toggle_children = -1, collapse_all = -1;
 	uint64_t old_cputimes = 0;
 	atomic<int> numpids = 0;
 	int filter_found = 0;
@@ -1362,6 +1362,21 @@ namespace Proc {
 				}
 				collapse = expand = -1;
 			}
+
+			if (collapse_all != -1) {
+				//? If any parent process is currently expanded, collapse all; otherwise expand all
+				std::unordered_set<size_t> parent_pids;
+				for (const auto& p : current_procs)
+					parent_pids.insert(static_cast<size_t>(p.ppid));
+				const bool do_collapse = rng::any_of(current_procs, [&parent_pids](const proc_info& p) {
+					return parent_pids.contains(p.pid) and not p.collapsed;
+				});
+				for (auto& p : current_procs)
+					p.collapsed = do_collapse;
+				collapse_all = -1;
+				if (Config::ints.at("proc_selected") > 0) locate_selection = true;
+			}
+
 			if (should_filter or not filter.empty()) filter_found = 0;
 
 			vector<tree_proc> tree_procs;
diff --git a/src/openbsd/btop_collect.cpp b/src/openbsd/btop_collect.cpp
index bb822dd..e5557c3 100644
--- a/src/openbsd/btop_collect.cpp
+++ b/src/openbsd/btop_collect.cpp
@@ -991,7 +991,7 @@ namespace Proc {
 	fs::file_time_type passwd_time;
 
 	uint64_t cputimes;
-	int collapse = -1, expand = -1, toggle_children = -1;
+	int collapse = -1, expand = -1, toggle_children = -1, collapse_all = -1;
 	uint64_t old_cputimes = 0;
 	atomic<int> numpids = 0;
 	int filter_found = 0;
@@ -1265,6 +1265,21 @@ namespace Proc {
 				}
 				collapse = expand = -1;
 			}
+
+			if (collapse_all != -1) {
+				//? If any parent process is currently expanded, collapse all; otherwise expand all
+				std::unordered_set<size_t> parent_pids;
+				for (const auto& p : current_procs)
+					parent_pids.insert(static_cast<size_t>(p.ppid));
+				const bool do_collapse = rng::any_of(current_procs, [&parent_pids](const proc_info& p) {
+					return parent_pids.contains(p.pid) and not p.collapsed;
+				});
+				for (auto& p : current_procs)
+					p.collapsed = do_collapse;
+				collapse_all = -1;
+				if (Config::ints.at("proc_selected") > 0) locate_selection = true;
+			}
+
 			if (should_filter or not filter.empty()) filter_found = 0;
 
 			vector<tree_proc> tree_procs;
diff --git a/src/osx/btop_collect.cpp b/src/osx/btop_collect.cpp
index b720bb2..49f65e8 100644
--- a/src/osx/btop_collect.cpp
+++ b/src/osx/btop_collect.cpp
@@ -1590,7 +1590,7 @@ namespace Proc {
 	fs::file_time_type passwd_time;
 
 	uint64_t cputimes;
-	int collapse = -1, expand = -1, toggle_children = -1;
+	int collapse = -1, expand = -1, toggle_children = -1, collapse_all = -1;
 	uint64_t old_cputimes = 0;
 	atomic<int> numpids = 0;
 	int filter_found = 0;
@@ -1922,6 +1922,21 @@ namespace Proc {
 				}
 				collapse = expand = -1;
 			}
+
+			if (collapse_all != -1) {
+				//? If any parent process is currently expanded, collapse all; otherwise expand all
+				std::unordered_set<size_t> parent_pids;
+				for (const auto& p : current_procs)
+					parent_pids.insert(static_cast<size_t>(p.ppid));
+				const bool do_collapse = rng::any_of(current_procs, [&parent_pids](const proc_info& p) {
+					return parent_pids.contains(p.pid) and not p.collapsed;
+				});
+				for (auto& p : current_procs)
+					p.collapsed = do_collapse;
+				collapse_all = -1;
+				if (Config::ints.at("proc_selected") > 0) locate_selection = true;
+			}
+
 			if (should_filter or not filter.empty()) filter_found = 0;
 
 			vector<tree_proc> tree_procs;