diff --git a/python3/vimspector/debug_session.py b/python3/vimspector/debug_session.py
index 6fb0b16..4a89cdf 100644
--- a/python3/vimspector/debug_session.py
+++ b/python3/vimspector/debug_session.py
@@ -655,6 +655,37 @@ class DebugSession( object ):
     vim.command( 'tab split' )
     self._uiTab = vim.current.tabpage
 
+    mode = settings.Get( 'ui_mode' )
+
+    self._logger.debug( 'ui_mode = %s', mode )
+
+    if mode == 'auto':
+      # Go vertical if there isn't enough horizontal space for at least:
+      #  the left bar width
+      #  + the code min width
+      #  + the terminal min width
+      #  + enough space for a sign column and number column?
+      min_width = ( settings.Int( 'sidebar_width' )
+                    + 1 + 2 + 3
+                    + settings.Int( 'code_minwidth' )
+                    + 1 + settings.Int( 'terminal_minwidth' ) )
+
+      mode = ( 'vertical'
+               if vim.options[ 'columns' ] < min_width
+               else 'horizontal' )
+
+      self._logger.debug( 'min_width: %s, actual: %s - result: %s',
+                          min_width,
+                          vim.options[ 'columns' ],
+                          mode )
+
+    if mode == 'vertical':
+      self._SetUpUIVertical()
+    else:
+      self._SetUpUIHorizontal()
+
+
+  def _SetUpUIHorizontal( self ):
     # Code window
     code_window = vim.current.window
     self._codeView = code.CodeView( code_window, self._api_prefix )
@@ -695,6 +726,66 @@ class DebugSession( object ):
     # TODO: If/when we support multiple sessions, we'll need some way to
     # indicate which tab was created and store all the tabs
     vim.vars[ 'vimspector_session_windows' ] = {
+      'mode': 'horizontal',
+      'tabpage': self._uiTab.number,
+      'code': utils.WindowID( code_window, self._uiTab ),
+      'stack_trace': utils.WindowID( stack_trace_window, self._uiTab ),
+      'variables': utils.WindowID( vars_window, self._uiTab ),
+      'watches': utils.WindowID( watch_window, self._uiTab ),
+      'output': utils.WindowID( output_window, self._uiTab ),
+      'eval': None # this is going to be updated every time eval popup is opened
+    }
+    with utils.RestoreCursorPosition():
+      with utils.RestoreCurrentWindow():
+        with utils.RestoreCurrentBuffer( vim.current.window ):
+          vim.command( 'doautocmd User VimspectorUICreated' )
+
+
+  def _SetUpUIVertical( self ):
+    # Code window
+    code_window = vim.current.window
+    self._codeView = code.CodeView( code_window, self._api_prefix )
+
+    # Call stack
+    vim.command(
+      f'topleft { settings.Int( "topbar_height" ) }new' )
+    stack_trace_window = vim.current.window
+    one_third = int( vim.eval( 'winwidth( 0 )' ) ) / 3
+    self._stackTraceView = stack_trace.StackTraceView( self,
+                                                       stack_trace_window )
+
+
+    # Watches
+    vim.command( 'leftabove vertical new' )
+    watch_window = vim.current.window
+
+    # Variables
+    vim.command( 'leftabove vertical new' )
+    vars_window = vim.current.window
+
+
+    with utils.LetCurrentWindow( vars_window ):
+      vim.command( f'{ one_third }wincmd |' )
+    with utils.LetCurrentWindow( watch_window ):
+      vim.command( f'{ one_third }wincmd |' )
+    with utils.LetCurrentWindow( stack_trace_window ):
+      vim.command( f'{ one_third }wincmd |' )
+
+    self._variablesView = variables.VariablesView( vars_window,
+                                                   watch_window )
+
+
+    # Output/logging
+    vim.current.window = code_window
+    vim.command( f'rightbelow { settings.Int( "bottombar_height" ) }new' )
+    output_window = vim.current.window
+    self._outputView = output.DAPOutputView( output_window,
+                                             self._api_prefix )
+
+    # TODO: If/when we support multiple sessions, we'll need some way to
+    # indicate which tab was created and store all the tabs
+    vim.vars[ 'vimspector_session_windows' ] = {
+      'mode': 'vertical',
       'tabpage': self._uiTab.number,
       'code': utils.WindowID( code_window, self._uiTab ),
       'stack_trace': utils.WindowID( stack_trace_window, self._uiTab ),
diff --git a/python3/vimspector/settings.py b/python3/vimspector/settings.py
index 9ad9e41..e9e76ea 100644
--- a/python3/vimspector/settings.py
+++ b/python3/vimspector/settings.py
@@ -20,11 +20,20 @@ from vimspector import utils
 
 DEFAULTS = {
   # UI
-  'bottombar_height':  10,
-  'sidebar_width':     50,
-  'code_minwidth':     82,
-  'terminal_maxwidth': 80,
-  'terminal_minwidth': 10,
+  'ui_mode':            'auto',
+  'bottombar_height':   10,
+
+  # For ui_mode = 'horizontal':
+  'sidebar_width':      50,
+  'code_minwidth':      82,
+  'terminal_maxwidth':  80,
+  'terminal_minwidth':  10,
+
+  # For ui_mode = 'vertical':
+  'topbar_height':      15,
+  'code_minheight':     20,
+  'terminal_maxheight': 15,
+  'terminal_minheight': 5,
 
   # Signs
   'sign_priority': {
diff --git a/python3/vimspector/terminal.py b/python3/vimspector/terminal.py
index 6ffd56a..0c84704 100644
--- a/python3/vimspector/terminal.py
+++ b/python3/vimspector/terminal.py
@@ -23,12 +23,53 @@ def LaunchTerminal( api_prefix,
   env = params.get( 'env' ) or {}
 
   term_options = {
-    'vertical': 1,
     'norestore': 1,
     'cwd': cwd,
     'env': env,
   }
 
+  if settings.Get( 'ui_mode' ) == 'horizontal':
+    # force-horizontal
+    term_options[ 'vertical' ] = 1
+  elif utils.GetVimValue( vim.vars[ 'vimspector_session_windows' ],
+                          'mode' ) == 'horizontal':
+    # horizontal, which means that we should have enough space for:
+    #  - sidebar
+    #  - code min
+    #  - term min width
+    #  - + 2 vertical spaders
+    #  - + 3 columns for signs
+    term_options[ 'vertical' ] = 1
+
+    # if we don't have enough space for terminal_maxwidth, then see if we have
+    # enough vertically for terminal_maxheight, in which case,
+    # that seems a better fit
+    term_horiz_max = ( settings.Int( 'sidebar_width' ) +
+                       1 + 2 + 3 +
+                       settings.Int( 'code_minwidth' ) +
+                       1 + settings.Int( 'terminal_maxwidth' ) )
+    term_vert_max = ( settings.Int( 'bottombar_height' ) + 1 +
+                      settings.Int( 'code_minheight' ) + 1 +
+                      settings.Int( 'terminal_minheight' ) )
+
+    if ( vim.options[ 'columns' ] < term_horiz_max and
+         vim.options[ 'lines' ] >= term_vert_max ):
+      # Looks like it, let's try that layout
+      term_options[ 'vertical' ] = 0
+
+
+  else:
+    # vertical - we need enough space horizontally for the code+terminal, but we
+    # may fit better with code above terminal
+    term_options[ 'vertical' ] = 0
+
+    term_horiz_max = ( settings.Int( 'code_minwidth' ) + 3 +
+                       settings.Int( 'terminal_maxwidth' ) + 1 )
+
+    if vim.options[ 'columns' ] > term_horiz_max:
+      term_options[ 'vertical' ] = 1
+
+
   if not window_for_start or not window_for_start.valid:
     # TOOD: Where? Maybe we should just use botright vertical ...
     window_for_start = vim.current.window
@@ -50,13 +91,23 @@ def LaunchTerminal( api_prefix,
     # If we're making a vertical split from the code window, make it no more
     # than 80 columns and no fewer than 10. Also try and keep the code window
     # at least 82 columns
-    if term_options[ 'vertical' ] and not term_options.get( 'curwin', 0 ):
+    if term_options.get( 'curwin', 0 ):
+      pass
+    elif term_options[ 'vertical' ]:
       term_options[ 'term_cols' ] = max(
         min ( int( vim.eval( 'winwidth( 0 )' ) )
                    - settings.Int( 'code_minwidth' ),
               settings.Int( 'terminal_maxwidth' ) ),
         settings.Int( 'terminal_minwidth' )
       )
+    else:
+      term_options[ 'term_rows' ] = max(
+        min ( int( vim.eval( 'winheight( 0 )' ) )
+                   - settings.Int( 'code_minheight' ),
+              settings.Int( 'terminal_maxheight' ) ),
+        settings.Int( 'terminal_minheight' )
+      )
+
 
     buffer_number = int(
       utils.Call(
diff --git a/tests/lib/autoload/vimspector/test/setup.vim b/tests/lib/autoload/vimspector/test/setup.vim
index b0296e0..6ab220c 100644
--- a/tests/lib/autoload/vimspector/test/setup.vim
+++ b/tests/lib/autoload/vimspector/test/setup.vim
@@ -50,3 +50,59 @@ function! vimspector#test#setup#Reset() abort
   call popup_clear()
 endfunction
 
+let s:g_stack = {}
+
+function! vimspector#test#setup#PushGlobal( name, value ) abort
+  if !has_key( s:g_stack, a:name )
+    let s:g_stack[ a:name ] = []
+  endif
+
+  let old_value = get( g:, a:name, v:null )
+  call add( s:g_stack[ a:name ], old_value )
+  let g:[ a:name ] = a:value
+
+  return old_value
+endfunction
+
+function! vimspector#test#setup#PopGlobal( name ) abort
+  if !has_key( s:g_stack, a:name ) || len( s:g_stack[ a:name ] ) == 0
+    return v:null
+  endif
+
+  let old_value = s:g_stack[ a:name ][ -1 ]
+  call remove( s:g_stack[ a:name ], -1 )
+
+  if old_value is v:null
+    silent! call remove( g:, a:name )
+  else
+    let g:[ a:name ] = old_value
+  endif
+
+  return old_value
+endfunction
+
+let s:o_stack = {}
+
+function! vimspector#test#setup#PushOption( name, value ) abort
+  if !has_key( s:o_stack, a:name )
+    let s:o_stack[ a:name ] = []
+  endif
+
+  let old_value = v:null
+  execute 'let old_value = &' . a:name
+  call add( s:o_stack[ a:name ], old_value )
+  execute 'set ' . a:name . '=' . a:value
+  return old_value
+endfunction
+
+function! vimspector#test#setup#PopOption( name ) abort
+  if !has_key( s:o_stack, a:name ) || len( s:o_stack[ a:name ] ) == 0
+    return v:null
+  endif
+
+  let old_value = s:o_stack[ a:name ][ -1 ]
+  call remove( s:o_stack[ a:name ], -1 )
+
+  execute 'set ' . a:name . '=' . old_value
+  return old_value
+endfunction
diff --git a/tests/ui.test.vim b/tests/ui.test.vim
index f251539..1f7789e 100644
--- a/tests/ui.test.vim
+++ b/tests/ui.test.vim
@@ -1,6 +1,7 @@
 let s:fn='../support/test/python/simple_python/main.py'
 
 function! SetUp()
+  let g:vimspector_ui_mode = get( s:, 'vimspector_ui_mode', 'horizontal' )
   call vimspector#test#setup#SetUpWithMappings( 'HUMAN' )
 endfunction
 
@@ -16,12 +17,17 @@ function! s:StartDebugging()
   call vimspector#test#signs#AssertCursorIsAtLineInBuffer( s:fn, 23, 1 )
 endfunction
 
+function! SetUp_Test_StandardLayout()
+  call vimspector#test#setup#PushOption( 'columns', 200 )
+endfunction
+
 function! Test_StandardLayout()
   call s:StartDebugging()
 
   call vimspector#StepOver()
   call vimspector#test#signs#AssertCursorIsAtLineInBuffer( s:fn, 25, 1 )
 
+  call assert_equal( 'horizontal', g:vimspector_session_windows.mode )
   call assert_equal(
         \ [ 'row', [
         \   [ 'col', [
@@ -43,6 +49,247 @@ function! Test_StandardLayout()
   %bwipe!
 endfunction
 
+function! TearDown_Test_StandardLayout()
+  call vimspector#test#setup#PopOption( 'columns' )
+endfunction
+
+function! SetUp_Test_NarrowLayout()
+  call vimspector#test#setup#PushOption( 'columns', 100 )
+  let s:vimspector_ui_mode = 'vertical'
+endfunction
+
+function! Test_NarrowLayout()
+  call s:StartDebugging()
+
+  call vimspector#StepOver()
+  call vimspector#test#signs#AssertCursorIsAtLineInBuffer( s:fn, 25, 1 )
+
+  call assert_equal( 'vertical', g:vimspector_session_windows.mode )
+  call assert_equal(
+        \ [ 'col', [
+        \   [ 'row', [
+        \     [ 'leaf', g:vimspector_session_windows.variables ],
+        \     [ 'leaf', g:vimspector_session_windows.watches ],
+        \     [ 'leaf', g:vimspector_session_windows.stack_trace ],
+        \   ] ],
+        \   [ 'leaf', g:vimspector_session_windows.code ],
+        \   [ 'leaf', g:vimspector_session_windows.terminal ],
+        \   [ 'leaf', g:vimspector_session_windows.output ],
+        \ ] ],
+        \ winlayout( g:vimspector_session_windows.tabpage ) )
+
+  call vimspector#test#setup#Reset()
+  %bwipe!
+endfunction
+
+function! TearDown_Test_NarrowLayout()
+  unlet s:vimspector_ui_mode
+  call vimspector#test#setup#PopOption( 'columns' )
+endfunction
+
+function! SetUp_Test_AutoLayoutTerminalVert()
+  let s:vimspector_ui_mode = 'auto'
+  call vimspector#test#setup#PushOption( 'columns', 250 )
+  call vimspector#test#setup#PushOption( 'lines', 30 )
+endfunction
+
+function! Test_AutoLayoutTerminalVert()
+  call s:StartDebugging()
+
+  call vimspector#StepOver()
+  call vimspector#test#signs#AssertCursorIsAtLineInBuffer( s:fn, 25, 1 )
+
+  call assert_equal( 'horizontal', g:vimspector_session_windows.mode )
+  call assert_equal(
+        \ [ 'row', [
+        \   [ 'col', [
+        \     [ 'leaf', g:vimspector_session_windows.variables ],
+        \     [ 'leaf', g:vimspector_session_windows.watches ],
+        \     [ 'leaf', g:vimspector_session_windows.stack_trace ],
+        \   ] ],
+        \   [ 'col', [
+        \     [ 'row', [
+        \       [ 'leaf', g:vimspector_session_windows.code ],
+        \       [ 'leaf', g:vimspector_session_windows.terminal ],
+        \     ] ],
+        \     [ 'leaf', g:vimspector_session_windows.output ],
+        \   ] ]
+        \ ] ],
+        \ winlayout( g:vimspector_session_windows.tabpage ) )
+
+  call vimspector#test#setup#Reset()
+  %bwipe!
+endfunction
+
+function! TearDown_Test_AutoLayoutTerminalVert()
+  unlet s:vimspector_ui_mode
+  call vimspector#test#setup#PopOption( 'lines' )
+  call vimspector#test#setup#PopOption( 'columns' )
+endfunction
+
+function! SetUp_Test_AutoLayoutTerminalHorizVert()
+  let s:vimspector_ui_mode = 'auto'
+  " Wide enough to be horizontal layout, but not wide enough to fully fit the
+  " terminal, with enough rows to fit the max terminal below
+  call vimspector#test#setup#PushOption( 'columns',
+        \ 50 + 82 + 3 + 2 + 12 )
+  call vimspector#test#setup#PushOption( 'lines', 50 )
+endfunction
+
+function! Test_AutoLayoutTerminalHorizVert()
+  call s:StartDebugging()
+
+  call vimspector#StepOver()
+  call vimspector#test#signs#AssertCursorIsAtLineInBuffer( s:fn, 25, 1 )
+
+  call assert_equal( 'horizontal', g:vimspector_session_windows.mode )
+  call assert_equal(
+        \ [ 'row', [
+        \   [ 'col', [
+        \     [ 'leaf', g:vimspector_session_windows.variables ],
+        \     [ 'leaf', g:vimspector_session_windows.watches ],
+        \     [ 'leaf', g:vimspector_session_windows.stack_trace ],
+        \   ] ],
+        \   [ 'col', [
+        \     [ 'leaf', g:vimspector_session_windows.code ],
+        \     [ 'leaf', g:vimspector_session_windows.terminal ],
+        \     [ 'leaf', g:vimspector_session_windows.output ],
+        \   ] ]
+        \ ] ],
+        \ winlayout( g:vimspector_session_windows.tabpage ) )
+
+  call vimspector#test#setup#Reset()
+  %bwipe!
+endfunction
+
+function! TearDown_Test_AutoLayoutTerminalHorizVert()
+  unlet s:vimspector_ui_mode
+  call vimspector#test#setup#PopOption( 'lines' )
+  call vimspector#test#setup#PopOption( 'columns' )
+endfunction
+
+function! SetUp_Test_AutoLayoutTerminalHorizVertButNotEnoughLines()
+  let s:vimspector_ui_mode = 'auto'
+  " Wide enough to be horizontal layout, but not wide enough to fully fit the
+  " terminal, with enough rows to fit the max terminal below, but there are not
+  " enough lines to do this
+  call vimspector#test#setup#PushOption( 'columns',
+        \ 50 + 82 + 3 + 2 + 12 )
+  call vimspector#test#setup#PushOption( 'lines', 20 )
+endfunction
+
+function! Test_AutoLayoutTerminalHorizVertButNotEnoughLines()
+  call s:StartDebugging()
+
+  call vimspector#StepOver()
+  call vimspector#test#signs#AssertCursorIsAtLineInBuffer( s:fn, 25, 1 )
+
+  call assert_equal( 'horizontal', g:vimspector_session_windows.mode )
+  call assert_equal(
+        \ [ 'row', [
+        \   [ 'col', [
+        \     [ 'leaf', g:vimspector_session_windows.variables ],
+        \     [ 'leaf', g:vimspector_session_windows.watches ],
+        \     [ 'leaf', g:vimspector_session_windows.stack_trace ],
+        \   ] ],
+        \   [ 'col', [
+        \     [ 'row', [
+        \       [ 'leaf', g:vimspector_session_windows.code ],
+        \       [ 'leaf', g:vimspector_session_windows.terminal ],
+        \     ] ],
+        \     [ 'leaf', g:vimspector_session_windows.output ],
+        \   ] ],
+        \ ] ],
+        \ winlayout( g:vimspector_session_windows.tabpage ) )
+
+  call vimspector#test#setup#Reset()
+  %bwipe!
+endfunction
+
+function! TearDown_Test_AutoLayoutTerminalHorizVertButNotEnoughLines()
+  unlet s:vimspector_ui_mode
+  call vimspector#test#setup#PopOption( 'lines' )
+  call vimspector#test#setup#PopOption( 'columns' )
+endfunction
+
+function! SetUp_Test_AutoLayoutTerminalHoriz()
+  let s:vimspector_ui_mode = 'vertical'
+  " Vertical layout, but we split the terminal horizonally
+  call vimspector#test#setup#PushOption( 'columns', 200 )
+  call vimspector#test#setup#PushOption( 'lines', 50 )
+endfunction
+
+function! Test_AutoLayoutTerminalHoriz()
+  call s:StartDebugging()
+
+  call vimspector#StepOver()
+  call vimspector#test#signs#AssertCursorIsAtLineInBuffer( s:fn, 25, 1 )
+
+  call assert_equal( 'vertical', g:vimspector_session_windows.mode )
+  call assert_equal(
+        \ [ 'col', [
+        \   [ 'row', [
+        \     [ 'leaf', g:vimspector_session_windows.variables ],
+        \     [ 'leaf', g:vimspector_session_windows.watches ],
+        \     [ 'leaf', g:vimspector_session_windows.stack_trace ],
+        \   ] ],
+        \   [ 'row', [
+        \     [ 'leaf', g:vimspector_session_windows.code ],
+        \     [ 'leaf', g:vimspector_session_windows.terminal ],
+        \   ] ],
+        \   [ 'leaf', g:vimspector_session_windows.output ],
+        \ ] ],
+        \ winlayout( g:vimspector_session_windows.tabpage ) )
+
+  call vimspector#test#setup#Reset()
+  %bwipe!
+endfunction
+
+function! TearDown_Test_AutoLayoutTerminalHoriz()
+  unlet s:vimspector_ui_mode
+  call vimspector#test#setup#PopOption( 'lines' )
+  call vimspector#test#setup#PopOption( 'columns' )
+endfunction
+
+function! SetUp_Test_AutoLayoutTerminalVertVert()
+  let s:vimspector_ui_mode = 'auto'
+  " Not wide enough to go horizontal, but wide enough to put the terminal and
+  " code vertically split
+  call vimspector#test#setup#PushOption( 'columns', 80 )
+  call vimspector#test#setup#PushOption( 'lines', 30 )
+endfunction
+
+function! Test_AutoLayoutTerminalVertVert()
+  call s:StartDebugging()
+
+  call vimspector#StepOver()
+  call vimspector#test#signs#AssertCursorIsAtLineInBuffer( s:fn, 25, 1 )
+
+  call assert_equal( 'vertical', g:vimspector_session_windows.mode )
+  call assert_equal(
+        \ [ 'col', [
+        \   [ 'row', [
+        \     [ 'leaf', g:vimspector_session_windows.variables ],
+        \     [ 'leaf', g:vimspector_session_windows.watches ],
+        \     [ 'leaf', g:vimspector_session_windows.stack_trace ],
+        \   ] ],
+        \   [ 'leaf', g:vimspector_session_windows.code ],
+        \   [ 'leaf', g:vimspector_session_windows.terminal ],
+        \   [ 'leaf', g:vimspector_session_windows.output ],
+        \ ] ],
+        \ winlayout( g:vimspector_session_windows.tabpage ) )
+
+  call vimspector#test#setup#Reset()
+  %bwipe!
+endfunction
+
+function! TearDown_Test_AutoLayoutTerminalVertVert()
+  unlet s:vimspector_ui_mode
+  call vimspector#test#setup#PopOption( 'lines' )
+  call vimspector#test#setup#PopOption( 'columns' )
+endfunction
+
+
 function! Test_CloseVariables()
   call s:StartDebugging()