diff --git a/NEWS.md b/NEWS.md
index 39810e08535d4..4d4de48c603da 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -168,6 +168,11 @@ Deprecated or removed
   * `randbool` is deprecated. Use `rand(Bool)` to produce a random boolean value, and
     `bitrand` to produce a random BitArray ([#9105], [#9569]).
 
+REPL improvements
+-----------------
+
+  * Undo via Ctrl-/ and Ctrl-_
+
 Julia v0.3.0 Release Notes
 ==========================
 
diff --git a/base/LineEdit.jl b/base/LineEdit.jl
index 0fb95c1908133..9552abdc49fc2 100644
--- a/base/LineEdit.jl
+++ b/base/LineEdit.jl
@@ -55,6 +55,7 @@ type PromptState <: ModeState
     terminal::TextTerminal
     p::Prompt
     input_buffer::IOBuffer
+    undo_buffers::Vector{IOBuffer}
     ias::InputAreaState
     indent::Int
 end
@@ -87,7 +88,8 @@ terminal(s::PromptState) = s.terminal
 
 for f in [:terminal, :edit_insert, :on_enter, :add_history, :buffer, :edit_backspace, :(Base.isempty),
         :replace_line, :refresh_multi_line, :input_string, :edit_move_left, :edit_move_right,
-        :edit_move_word_left, :edit_move_word_right, :update_display_buffer]
+        :edit_move_word_left, :edit_move_word_right, :update_display_buffer,
+        :empty_undo, :push_undo, :pop_undo]
     @eval ($f)(s::MIState, args...) = $(f)(s.mode_state[s.current_mode], args...)
 end
 
@@ -146,16 +148,14 @@ function complete_line(s::PromptState, repeats)
     elseif length(completions) == 1
         # Replace word by completion
         prev_pos = position(s.input_buffer)
-        seek(s.input_buffer, prev_pos-sizeof(partial))
-        edit_replace(s, position(s.input_buffer), prev_pos, completions[1])
+        edit_replace(s, prev_pos-sizeof(partial), prev_pos, completions[1])
     else
         p = common_prefix(completions)
         if length(p) > 0 && p != partial
             # All possible completions share the same prefix, so we might as
             # well complete that
             prev_pos = position(s.input_buffer)
-            seek(s.input_buffer, prev_pos-sizeof(partial))
-            edit_replace(s, position(s.input_buffer), prev_pos, p)
+            edit_replace(s, prev_pos-sizeof(partial), prev_pos, p)
         elseif repeats > 0
             show_completions(s, completions)
         end
@@ -479,10 +479,12 @@ function splice_buffer!{T<:Integer}(buf::IOBuffer, r::UnitRange{T}, ins::Abstrac
 end
 
 function edit_replace(s, from, to, str)
+    push_undo(s)
     splice_buffer!(buffer(s), from:to-1, str)
 end
 
 function edit_insert(s::PromptState, c)
+    push_undo(s)
     str = string(c)
     edit_insert(s.input_buffer, str)
     if !('\n' in str) && eof(s.input_buffer) &&
@@ -503,9 +505,11 @@ function edit_insert(buf::IOBuffer, c)
 end
 
 function edit_backspace(s::PromptState)
+    push_undo(s)
     if edit_backspace(s.input_buffer)
         refresh_line(s)
     else
+        pop_undo(s)
         beep(terminal(s))
     end
 end
@@ -520,7 +524,15 @@ function edit_backspace(buf::IOBuffer)
     end
 end
 
-edit_delete(s) = edit_delete(buffer(s)) ? refresh_line(s) : beep(terminal(s))
+function edit_delete(s)
+    push_undo(s)
+    if edit_delete(buffer(s))
+        refresh_line(s)
+    else
+        pop_undo(s)
+        beep(terminal(s))
+    end
+end
 function edit_delete(buf::IOBuffer)
     eof(buf) && return false
     oldpos = position(buf)
@@ -538,7 +550,8 @@ function edit_werase(buf::IOBuffer)
     true
 end
 function edit_werase(s)
-    edit_werase(buffer(s)) && refresh_line(s)
+    push_undo(s)
+    edit_werase(buffer(s)) ? refresh_line(s) : pop_undo(s)
 end
 
 function edit_delete_prev_word(buf::IOBuffer)
@@ -550,7 +563,8 @@ function edit_delete_prev_word(buf::IOBuffer)
     true
 end
 function edit_delete_prev_word(s)
-    edit_delete_prev_word(buffer(s)) && refresh_line(s)
+    push_undo(s)
+    edit_delete_prev_word(buffer(s)) ? refresh_line(s) : pop_undo(s)
 end
 
 function edit_delete_next_word(buf::IOBuffer)
@@ -562,15 +576,18 @@ function edit_delete_next_word(buf::IOBuffer)
     true
 end
 function edit_delete_next_word(s)
-    edit_delete_next_word(buffer(s)) && refresh_line(s)
+    push_undo(s)
+    edit_delete_next_word(buffer(s)) ? refresh_line(s) : pop_undo(s)
 end
 
 function edit_yank(s::MIState)
+    push_undo(s)
     edit_insert(buffer(s), s.kill_buffer)
     refresh_line(s)
 end
 
 function edit_kill_line(s::MIState)
+    push_undo(s)
     buf = buffer(s)
     pos = position(buf)
     killbuf = readline(buf)
@@ -584,7 +601,10 @@ function edit_kill_line(s::MIState)
     refresh_line(s)
 end
 
-edit_transpose(s) = edit_transpose(buffer(s)) && refresh_line(s)
+function edit_transpose(s)
+    push_undo(s)
+    edit_transpose(buffer(s)) ? refresh_line(s) : pop_undo(s)
+end
 function edit_transpose(buf::IOBuffer)
     position(buf) == 0 && return false
     eof(buf) && char_move_left(buf)
@@ -599,15 +619,18 @@ end
 edit_clear(buf::IOBuffer) = truncate(buf, 0)
 
 function edit_clear(s::MIState)
+    push_undo(s)
     edit_clear(buffer(s))
     refresh_line(s)
 end
 
 function replace_line(s::PromptState, l::IOBuffer)
+    empty_undo(s)
     s.input_buffer = l
 end
 
 function replace_line(s::PromptState, l)
+    empty_undo(s)
     s.input_buffer.ptr = 1
     s.input_buffer.size = 0
     write(s.input_buffer, l)
@@ -1112,8 +1135,7 @@ function complete_line(s::SearchState, repeats)
     # For now only allow exact completions in search mode
     if length(completions) == 1
         prev_pos = position(s.query_buffer)
-        seek(s.query_buffer, prev_pos-sizeof(partial))
-        edit_replace(s, position(s.query_buffer), prev_pos, completions[1])
+        edit_replace(s, prev_pos-sizeof(partial), prev_pos, completions[1])
     end
 end
 
@@ -1345,6 +1367,9 @@ AnyDict(
     # Meta Enter
     "\e\r" => (s,o...)->(edit_insert(s, '\n')),
     "\e\n" => "\e\r",
+    # Undo: Ctrl-/ or Ctrl-_
+    "^/" => (s,o...)->(pop_undo(s) ? refresh_line(s) : beep(terminal(s))),
+    "^_" => "^/",
     # Simply insert it into the buffer by default
     "*" => (s,data,c)->(edit_insert(s, c)),
     "^U" => (s,o...)->edit_clear(s),
@@ -1483,6 +1508,7 @@ function reset_state(s::PromptState)
         s.input_buffer.size = 0
         s.input_buffer.ptr = 1
     end
+    empty_undo(s)
     s.ias = InputAreaState(0, 0)
 end
 
@@ -1512,7 +1538,7 @@ end
 
 run_interface(::Prompt) = nothing
 
-init_state(terminal, prompt::Prompt) = PromptState(terminal, prompt, IOBuffer(), InputAreaState(1, 1), length(prompt.prompt))
+init_state(terminal, prompt::Prompt) = PromptState(terminal, prompt, IOBuffer(), (IOBuffer)[], InputAreaState(1, 1), length(prompt.prompt))
 
 function init_state(terminal, m::ModalInterface)
     s = MIState(m, m.modes[1], false, Dict{Any,Any}())
@@ -1539,6 +1565,23 @@ buffer(s::PromptState) = s.input_buffer
 buffer(s::SearchState) = s.query_buffer
 buffer(s::PrefixSearchState) = s.response_buffer
 
+function empty_undo(s::PromptState)
+    empty!(s.undo_buffers)
+end
+empty_undo(s) = nothing
+
+function push_undo(s::PromptState)
+    push!(s.undo_buffers, copy(s.input_buffer))
+end
+push_undo(s) = nothing
+
+function pop_undo(s::PromptState)
+    length(s.undo_buffers) > 0 || return false
+    s.input_buffer = pop!(s.undo_buffers)
+    true
+end
+pop_undo(s) = nothing
+
 keymap(s::PromptState, prompt::Prompt) = prompt.keymap_dict
 keymap_data(s::PromptState, prompt::Prompt) = prompt.keymap_func_data
 keymap(ms::MIState, m::ModalInterface) = keymap(ms.mode_state[ms.current_mode], ms.current_mode)
diff --git a/doc/manual/interacting-with-julia.rst b/doc/manual/interacting-with-julia.rst
index f70ae683f2089..3326542e2f270 100644
--- a/doc/manual/interacting-with-julia.rst
+++ b/doc/manual/interacting-with-julia.rst
@@ -159,7 +159,7 @@ The Julia REPL makes great use of key bindings.  Several control-key bindings we
 +------------------------+----------------------------------------------------+
 | ``^T``                 | Transpose the characters about the cursor          |
 +------------------------+----------------------------------------------------+
-| Delete, ``^D``         | Forward delete one character (when buffer has text)|
+| ``^/``, ``^_``         | Undo                                               |
 +------------------------+----------------------------------------------------+
 
 Customizing keybindings
diff --git a/test/lineedit.jl b/test/lineedit.jl
index 0e12a0d2326c6..441024fe4f720 100644
--- a/test/lineedit.jl
+++ b/test/lineedit.jl
@@ -395,3 +395,96 @@ term = TestHelpers.FakeTerminal(IOBuffer(), IOBuffer(), IOBuffer())
 s = LineEdit.refresh_multi_line(termbuf, term, buf,
     Base.LineEdit.InputAreaState(0,0), "julia> ", indent = 7)
 @test s == Base.LineEdit.InputAreaState(3,1)
+
+# test Undo
+let
+    term = TestHelpers.FakeTerminal(IOBuffer(), IOBuffer(), IOBuffer())
+    s = LineEdit.init_state(term, ModalInterface([Prompt("test> ")]))
+    function bufferdata(s)
+        buf = LineEdit.buffer(s)
+        bytestring(buf.data[1:buf.size])
+    end
+
+    LineEdit.edit_insert(s, "one two three")
+
+    LineEdit.edit_delete_prev_word(s)
+    @test bufferdata(s) == "one two "
+    LineEdit.pop_undo(s)
+    @test bufferdata(s) == "one two three"
+
+    LineEdit.edit_insert(s, " four")
+    LineEdit.edit_insert(s, " five")
+    @test bufferdata(s) == "one two three four five"
+    LineEdit.pop_undo(s)
+    @test bufferdata(s) == "one two three four"
+    LineEdit.pop_undo(s)
+    @test bufferdata(s) == "one two three"
+
+    LineEdit.edit_clear(s)
+    @test bufferdata(s) == ""
+    LineEdit.pop_undo(s)
+    @test bufferdata(s) == "one two three"
+
+    LineEdit.edit_move_left(s)
+    LineEdit.edit_move_left(s)
+    LineEdit.edit_transpose(s)
+    @test bufferdata(s) == "one two there"
+    LineEdit.pop_undo(s)
+    @test bufferdata(s) == "one two three"
+
+    LineEdit.move_line_start(s)
+    LineEdit.edit_kill_line(s)
+    @test bufferdata(s) == ""
+    LineEdit.pop_undo(s)
+    @test bufferdata(s) == "one two three"
+
+    LineEdit.move_line_start(s)
+    LineEdit.edit_kill_line(s)
+    LineEdit.edit_yank(s)
+    LineEdit.edit_yank(s)
+    @test bufferdata(s) == "one two threeone two three"
+    LineEdit.pop_undo(s)
+    @test bufferdata(s) == "one two three"
+    LineEdit.pop_undo(s)
+    @test bufferdata(s) == ""
+    LineEdit.pop_undo(s)
+    @test bufferdata(s) == "one two three"
+
+    LineEdit.move_line_end(s)
+    LineEdit.edit_backspace(s)
+    LineEdit.edit_backspace(s)
+    LineEdit.edit_backspace(s)
+    @test bufferdata(s) == "one two th"
+    LineEdit.pop_undo(s)
+    @test bufferdata(s) == "one two thr"
+    LineEdit.pop_undo(s)
+    @test bufferdata(s) == "one two thre"
+    LineEdit.pop_undo(s)
+    @test bufferdata(s) == "one two three"
+
+    LineEdit.edit_replace(s, 4, 7, "stott")
+    @test bufferdata(s) == "one stott three"
+    LineEdit.pop_undo(s)
+    @test bufferdata(s) == "one two three"
+
+    LineEdit.edit_move_left(s)
+    LineEdit.edit_move_left(s)
+    LineEdit.edit_move_left(s)
+    LineEdit.edit_delete(s)
+    @test bufferdata(s) == "one two thee"
+    LineEdit.pop_undo(s)
+    @test bufferdata(s) == "one two three"
+
+    LineEdit.edit_move_word_left(s)
+    LineEdit.edit_werase(s)
+    LineEdit.edit_delete_next_word(s)
+    @test bufferdata(s) == "one "
+    LineEdit.pop_undo(s)
+    @test bufferdata(s) == "one three"
+    LineEdit.pop_undo(s)
+    @test bufferdata(s) == "one two three"
+
+    # pop initial insert of "one two three"
+    LineEdit.pop_undo(s)
+    @test bufferdata(s) == ""
+end