diff --git a/data/core/commands/doc.lua b/data/core/commands/doc.lua
index 8e2078f3..54b84921 100644
--- a/data/core/commands/doc.lua
+++ b/data/core/commands/doc.lua
@@ -97,6 +97,67 @@ local function set_cursor(x, y, snap_type)
   core.blink_reset()
 end
 
+local function line_comment(comment, line1, line2)
+  local comment_text = comment .. " "
+  local uncomment = true
+  local start_offset = math.huge
+  for line = line1, line2 do
+    local text = doc().lines[line]
+    local s = text:find("%S")
+    local cs, ce = text:find(comment_text, s, true)
+    if s and cs ~= s then
+      uncomment = false
+      start_offset = math.min(start_offset, s)
+    end
+  end
+  for line = line1, line2 do
+    local text = doc().lines[line]
+    local s = text:find("%S")
+    if uncomment then
+      local cs, ce = text:find(comment_text, s, true)
+      if ce then
+        doc():remove(line, cs, line, ce + 1)
+      end
+    elseif s then
+      doc():insert(line, start_offset, comment_text)
+    end
+  end
+end
+
+local function block_comment(comment, line1, col1, line2, col2)
+  -- automatically skip spaces
+  local word_start = doc():get_text(line1, col1, line1, math.huge):find("%S")
+  local word_end = doc():get_text(line2, 1, line2, col2):find("%s*$")
+  col1 = col1 + (word_start and (word_start - 1) or 0)
+  col2 = word_end and word_end or col2
+
+  local block_start = doc():get_text(line1, col1, line1, col1 + #comment[1])
+  local block_end = doc():get_text(line2, col2 - #comment[2], line2, col2)
+
+  if block_start == comment[1] and block_end == comment[2] then
+    -- remove up to 1 whitespace after the comment
+    local start_len, stop_len = #comment[1], #comment[2]
+    if doc():get_text(line1, col1 + #comment[1], line1, col1 + #comment[1] + 1):find("%s$") then
+      start_len = start_len + 1
+    end
+    if doc():get_text(line2, col2 - #comment[2] - 1, line2, col2):find("^%s") then
+      stop_len = stop_len + 1
+    end
+
+    doc():remove(line1, col1, line1, col1 + start_len)
+    col2 = col2 - (line1 == line2 and start_len or 0)
+    doc():remove(line2, col2 - stop_len, line2, col2)
+
+    return line1, col1, line2, col2 - stop_len
+  else
+    doc():insert(line1, col1, comment[1] .. " ")
+    col2 = col2 + (line1 == line2 and (#comment[1] + 1) or 0)
+    doc():insert(line2, col2, " " .. comment[2])
+
+    return line1, col1, line2, col2 + #comment[2] + 1
+  end
+end
+
 local selection_commands = {
   ["doc:select-none"] = function()
     local line, col = doc():get_selection()
@@ -292,34 +353,43 @@ local commands = {
     end
   end,
 
+  ["doc:toggle-block-comments"] = function()
+    local comment = doc().syntax.block_comment
+    if not comment then
+      if doc().syntax.comment then
+        command.perform "doc:toggle-line-comments"
+      end
+      return
+    end
+
+    for idx, line1, col1, line2, col2 in doc_multiline_selections(true) do
+      -- if nothing is selected, toggle the whole line
+      if line1 == line2 and col1 == col2 then
+        col1 = 1
+        col2 = #doc().lines[line2]
+      end
+
+      line1, col1, line2, col2 = block_comment(comment, line1, col1, line2, col2)
+      doc():set_selections(idx, line1, col1, line2, col2)
+    end
+  end,
+
   ["doc:toggle-line-comments"] = function()
     local comment = doc().syntax.comment
-    if not comment then return end
-    local indentation = doc():get_indent_string()
-    local comment_text = comment .. " "
-    for idx, line1, _, line2 in doc_multiline_selections(true) do
-      local uncomment = true
-      local start_offset = math.huge
-      for line = line1, line2 do
-        local text = doc().lines[line]
-        local s = text:find("%S")
-        local cs, ce = text:find(comment_text, s, true)
-        if s and cs ~= s then
-          uncomment = false
-          start_offset = math.min(start_offset, s)
-        end
-      end
-      for line = line1, line2 do
-        local text = doc().lines[line]
-        local s = text:find("%S")
-        if uncomment then
-          local cs, ce = text:find(comment_text, s, true)
-          if ce then
-            doc():remove(line, cs, line, ce + 1)
-          end
-        elseif s then
-          doc():insert(line, start_offset, comment_text)
+    local block = false
+    if not comment then
+      comment = doc().syntax.block_comment
+      if not comment then return end
+      block = true
+    end
+
+    for _, line1, _, line2 in doc_multiline_selections(true) do
+      if block then
+        for line = line1, line2 do
+          block_comment(comment, line, 1, line, #doc().lines[line])
         end
+      else
+        line_comment(comment, line1, line2)
       end
     end
   end,
diff --git a/data/core/keymap.lua b/data/core/keymap.lua
index 404cff39..6716fca9 100644
--- a/data/core/keymap.lua
+++ b/data/core/keymap.lua
@@ -215,6 +215,7 @@ keymap.add_direct {
   ["ctrl+l"] = "doc:select-lines",
   ["ctrl+shift+l"] = { "find-replace:select-add-all", "doc:select-word" },
   ["ctrl+/"] = "doc:toggle-line-comments",
+  ["ctrl+shift+/"] = "doc:toggle-block-comments",
   ["ctrl+up"] = "doc:move-lines-up",
   ["ctrl+down"] = "doc:move-lines-down",
   ["ctrl+shift+d"] = "doc:duplicate-lines",
diff --git a/data/plugins/language_c.lua b/data/plugins/language_c.lua
index 88cc7c5a..c4d3b07b 100644
--- a/data/plugins/language_c.lua
+++ b/data/plugins/language_c.lua
@@ -5,6 +5,7 @@ syntax.add {
   name = "C",
   files = { "%.c$", "%.h$", "%.inl$" },
   comment = "//",
+  block_comment = { "/*", "*/" },
   patterns = {
     { pattern = "//.-\n",                type = "comment" },
     { pattern = { "/%*", "%*/" },        type = "comment" },
diff --git a/data/plugins/language_cpp.lua b/data/plugins/language_cpp.lua
index a945fd1f..2b3a104f 100644
--- a/data/plugins/language_cpp.lua
+++ b/data/plugins/language_cpp.lua
@@ -10,6 +10,7 @@ syntax.add {
     "%.c++$", "%.hh$", "%.H$", "%.hxx$", "%.hpp$", "%.h++$"
   },
   comment = "//",
+  block_comment = { "/*", "*/" },
   patterns = {
     { pattern = "//.-\n",                   type = "comment" },
     { pattern = { "/%*", "%*/" },           type = "comment" },
diff --git a/data/plugins/language_css.lua b/data/plugins/language_css.lua
index 395e375c..96c3eb8d 100644
--- a/data/plugins/language_css.lua
+++ b/data/plugins/language_css.lua
@@ -4,6 +4,7 @@ local syntax = require "core.syntax"
 syntax.add {
   name = "CSS",
   files = { "%.css$" },
+  block_comment = { "/*", "*/" },
   patterns = {
     { pattern = "\\.",                type = "normal"   },
     { pattern = "//.-\n",             type = "comment"  },
diff --git a/data/plugins/language_html.lua b/data/plugins/language_html.lua
index 1f4515bc..ff61fa7f 100644
--- a/data/plugins/language_html.lua
+++ b/data/plugins/language_html.lua
@@ -4,28 +4,29 @@ local syntax = require "core.syntax"
 syntax.add {
   name = "HTML",
   files = { "%.html?$" },
+  block_comment = { "<!--", "-->" },
   patterns = {
-    { 
-      pattern = { 
+    {
+      pattern = {
         "<%s*[sS][cC][rR][iI][pP][tT]%s+[tT][yY][pP][eE]%s*=%s*" ..
           "['\"]%a+/[jJ][aA][vV][aA][sS][cC][rR][iI][pP][tT]['\"]%s*>",
-        "<%s*/[sS][cC][rR][iI][pP][tT]>" 
-      },
-      syntax = ".js", 
-      type = "function" 
-    },
-    { 
-      pattern = { 
-        "<%s*[sS][cC][rR][iI][pP][tT]%s*>",
-        "<%s*/%s*[sS][cC][rR][iI][pP][tT]>" 
+        "<%s*/[sS][cC][rR][iI][pP][tT]>"
       },
       syntax = ".js",
       type = "function"
     },
-    { 
-      pattern = { 
-        "<%s*[sS][tT][yY][lL][eE][^>]*>", 
-        "<%s*/%s*[sS][tT][yY][lL][eE]%s*>" 
+    {
+      pattern = {
+        "<%s*[sS][cC][rR][iI][pP][tT]%s*>",
+        "<%s*/%s*[sS][cC][rR][iI][pP][tT]>"
+      },
+      syntax = ".js",
+      type = "function"
+    },
+    {
+      pattern = {
+        "<%s*[sS][tT][yY][lL][eE][^>]*>",
+        "<%s*/%s*[sS][tT][yY][lL][eE]%s*>"
       },
       syntax = ".css",
       type = "function"
diff --git a/data/plugins/language_js.lua b/data/plugins/language_js.lua
index 94ab8499..2e6d5d87 100644
--- a/data/plugins/language_js.lua
+++ b/data/plugins/language_js.lua
@@ -5,6 +5,7 @@ syntax.add {
   name = "JavaScript",
   files = { "%.js$", "%.json$", "%.cson$" },
   comment = "//",
+  block_comment = { "/*", "*/" },
   patterns = {
     { pattern = "//.-\n",               type = "comment"  },
     { pattern = { "/%*", "%*/" },       type = "comment"  },
diff --git a/data/plugins/language_lua.lua b/data/plugins/language_lua.lua
index 5c770d43..993e53c8 100644
--- a/data/plugins/language_lua.lua
+++ b/data/plugins/language_lua.lua
@@ -6,6 +6,7 @@ syntax.add {
   files = "%.lua$",
   headers = "^#!.*[ /]lua",
   comment = "--",
+  block_comment = { "--[[", "]]" },
   patterns = {
     { pattern = { '"', '"', '\\' },          type = "string" },
     { pattern = { "'", "'", '\\' },          type = "string" },
diff --git a/data/plugins/language_xml.lua b/data/plugins/language_xml.lua
index c858d3cf..297b6d73 100644
--- a/data/plugins/language_xml.lua
+++ b/data/plugins/language_xml.lua
@@ -5,6 +5,7 @@ syntax.add {
   name = "XML",
   files = { "%.xml$" },
   headers = "<%?xml",
+  block_comment = { "<!--", "-->" },
   patterns = {
     { pattern = { "<!%-%-", "%-%->" },     type = "comment"  },
     { pattern = { '%f[^>][^<]', '%f[<]' }, type = "normal"   },