diff --git a/README.md b/README.md
index ad28941..9f742fd 100644
--- a/README.md
+++ b/README.md
@@ -88,15 +88,15 @@ That's it! For more configuration options, see [Advanced Setup](#advanced-setup)
 The `<leader>as` keybinding has context-aware behavior:
 
 - **In normal buffers (visual mode)**: Sends selected text to Claude
-- **In nvim-tree/neo-tree buffers**: Adds the file under cursor (or selected files) to Claude's context
+- **In nvim-tree/neo-tree/oil.nvim buffers**: Adds the file under cursor (or selected files) to Claude's context
 
 This allows you to quickly add entire files to Claude's context for review, refactoring, or discussion.
 
 #### Features
 
 - **Single file**: Place cursor on any file and press `<leader>as`
-- **Multiple files**: Select multiple files (using tree plugin's selection features) and press `<leader>as`
-- **Smart detection**: Automatically detects whether you're in nvim-tree or neo-tree
+- **Multiple files**: Select multiple files (using tree plugin's selection features or visual selection in oil.nvim) and press `<leader>as`
+- **Smart detection**: Automatically detects whether you're in nvim-tree, neo-tree, or oil.nvim
 - **Error handling**: Clear feedback if no files are selected or if tree plugins aren't available
 
 ### Direct File Addition
diff --git a/lua/claudecode/diff.lua b/lua/claudecode/diff.lua
index ef44503..c16d65e 100644
--- a/lua/claudecode/diff.lua
+++ b/lua/claudecode/diff.lua
@@ -49,6 +49,7 @@ function M._find_main_editor_window()
         or filetype == "neo-tree-popup"
         or filetype == "ClaudeCode"
         or filetype == "NvimTree"
+        or filetype == "oil"
         or filetype == "aerial"
         or filetype == "tagbar"
       )
diff --git a/lua/claudecode/init.lua b/lua/claudecode/init.lua
index 2900099..2db3eb0 100644
--- a/lua/claudecode/init.lua
+++ b/lua/claudecode/init.lua
@@ -408,6 +408,7 @@ function M._create_commands()
 
     local is_tree_buffer = current_ft == "NvimTree"
       or current_ft == "neo-tree"
+      or current_ft == "oil"
       or string.match(current_bufname, "neo%-tree")
       or string.match(current_bufname, "NvimTree")
 
diff --git a/lua/claudecode/integrations.lua b/lua/claudecode/integrations.lua
index f5adeff..2827aab 100644
--- a/lua/claudecode/integrations.lua
+++ b/lua/claudecode/integrations.lua
@@ -1,6 +1,6 @@
 ---
 -- Tree integration module for ClaudeCode.nvim
--- Handles detection and selection of files from nvim-tree and neo-tree
+-- Handles detection and selection of files from nvim-tree, neo-tree, and oil.nvim
 -- @module claudecode.integrations
 local M = {}
 
@@ -14,6 +14,8 @@ function M.get_selected_files_from_tree()
     return M._get_nvim_tree_selection()
   elseif current_ft == "neo-tree" then
     return M._get_neotree_selection()
+  elseif current_ft == "oil" then
+    return M._get_oil_selection()
   else
     return nil, "Not in a supported tree buffer (current filetype: " .. current_ft .. ")"
   end
@@ -178,4 +180,85 @@ function M._get_neotree_selection()
   return {}, "No file found under cursor"
 end
 
+--- Get selected files from oil.nvim
+--- Supports both visual selection and single file under cursor
+--- @return table files List of file paths
+--- @return string|nil error Error message if operation failed
+function M._get_oil_selection()
+  local success, oil = pcall(require, "oil")
+  if not success then
+    return {}, "oil.nvim not available"
+  end
+
+  local bufnr = vim.api.nvim_get_current_buf() --[[@as number]]
+  local files = {}
+
+  -- Check if we're in visual mode
+  local mode = vim.fn.mode()
+  if mode == "V" or mode == "v" or mode == "\22" then
+    -- Visual mode: use the common visual range function
+    local visual_commands = require("claudecode.visual_commands")
+    local start_line, end_line = visual_commands.get_visual_range()
+
+    -- Get current directory once
+    local dir_ok, current_dir = pcall(oil.get_current_dir, bufnr)
+    if not dir_ok or not current_dir then
+      return {}, "Failed to get current directory"
+    end
+
+    -- Process each line in the visual selection
+    for line = start_line, end_line do
+      local entry_ok, entry = pcall(oil.get_entry_on_line, bufnr, line)
+      if entry_ok and entry and entry.name then
+        -- Skip parent directory entries
+        if entry.name ~= ".." and entry.name ~= "." then
+          local full_path = current_dir .. entry.name
+          -- Handle various entry types
+          if entry.type == "file" or entry.type == "link" then
+            table.insert(files, full_path)
+          elseif entry.type == "directory" then
+            -- Ensure directory paths end with /
+            table.insert(files, full_path:match("/$") and full_path or full_path .. "/")
+          else
+            -- For unknown types, return the path anyway
+            table.insert(files, full_path)
+          end
+        end
+      end
+    end
+
+    if #files > 0 then
+      return files, nil
+    end
+  else
+    -- Normal mode: get file under cursor with error handling
+    local ok, entry = pcall(oil.get_cursor_entry)
+    if not ok or not entry then
+      return {}, "Failed to get cursor entry"
+    end
+
+    local dir_ok, current_dir = pcall(oil.get_current_dir, bufnr)
+    if not dir_ok or not current_dir then
+      return {}, "Failed to get current directory"
+    end
+
+    -- Process the entry
+    if entry.name and entry.name ~= ".." and entry.name ~= "." then
+      local full_path = current_dir .. entry.name
+      -- Handle various entry types
+      if entry.type == "file" or entry.type == "link" then
+        return { full_path }, nil
+      elseif entry.type == "directory" then
+        -- Ensure directory paths end with /
+        return { full_path:match("/$") and full_path or full_path .. "/" }, nil
+      else
+        -- For unknown types, return the path anyway
+        return { full_path }, nil
+      end
+    end
+  end
+
+  return {}, "No file found under cursor"
+end
+
 return M
diff --git a/lua/claudecode/tools/open_file.lua b/lua/claudecode/tools/open_file.lua
index 49a777c..855a28b 100644
--- a/lua/claudecode/tools/open_file.lua
+++ b/lua/claudecode/tools/open_file.lua
@@ -75,6 +75,7 @@ local function find_main_editor_window()
         or filetype == "neo-tree-popup"
         or filetype == "ClaudeCode"
         or filetype == "NvimTree"
+        or filetype == "oil"
         or filetype == "aerial"
         or filetype == "tagbar"
       )
diff --git a/lua/claudecode/visual_commands.lua b/lua/claudecode/visual_commands.lua
index 4e76c41..4056728 100644
--- a/lua/claudecode/visual_commands.lua
+++ b/lua/claudecode/visual_commands.lua
@@ -166,6 +166,13 @@ function M.get_tree_state()
     end
 
     return nvim_tree_api, "nvim-tree"
+  elseif current_ft == "oil" then
+    local oil_success, oil = pcall(require, "oil")
+    if not oil_success then
+      return nil, nil
+    end
+
+    return oil, "oil"
   else
     return nil, nil
   end
@@ -338,6 +345,34 @@ function M.get_files_from_visual_selection(visual_data)
       end
     end
     files = unique_files
+  elseif tree_type == "oil" then
+    local oil = tree_state
+    local bufnr = vim.api.nvim_get_current_buf()
+
+    -- Get current directory once
+    local dir_ok, current_dir = pcall(oil.get_current_dir, bufnr)
+    if dir_ok and current_dir then
+      -- Access the process_oil_entry function through a module method
+      for line = start_pos, end_pos do
+        local entry_ok, entry = pcall(oil.get_entry_on_line, bufnr, line)
+        if entry_ok and entry and entry.name then
+          -- Skip parent directory entries
+          if entry.name ~= ".." and entry.name ~= "." then
+            local full_path = current_dir .. entry.name
+            -- Handle various entry types
+            if entry.type == "file" or entry.type == "link" then
+              table.insert(files, full_path)
+            elseif entry.type == "directory" then
+              -- Ensure directory paths end with /
+              table.insert(files, full_path:match("/$") and full_path or full_path .. "/")
+            else
+              -- For unknown types, return the path anyway
+              table.insert(files, full_path)
+            end
+          end
+        end
+      end
+    end
   end
 
   return files, nil
diff --git a/tests/unit/oil_integration_spec.lua b/tests/unit/oil_integration_spec.lua
new file mode 100644
index 0000000..235e7b0
--- /dev/null
+++ b/tests/unit/oil_integration_spec.lua
@@ -0,0 +1,229 @@
+-- luacheck: globals expect
+require("tests.busted_setup")
+
+describe("oil.nvim integration", function()
+  local integrations
+  local mock_vim
+
+  local function setup_mocks()
+    package.loaded["claudecode.integrations"] = nil
+    package.loaded["claudecode.visual_commands"] = nil
+    package.loaded["claudecode.logger"] = nil
+
+    -- Mock logger
+    package.loaded["claudecode.logger"] = {
+      debug = function() end,
+      warn = function() end,
+      error = function() end,
+    }
+
+    mock_vim = {
+      fn = {
+        mode = function()
+          return "n" -- Default to normal mode
+        end,
+        line = function(mark)
+          if mark == "'<" then
+            return 2
+          elseif mark == "'>" then
+            return 4
+          end
+          return 1
+        end,
+      },
+      api = {
+        nvim_get_current_buf = function()
+          return 1
+        end,
+        nvim_win_get_cursor = function()
+          return { 4, 0 }
+        end,
+        nvim_get_mode = function()
+          return { mode = "n" }
+        end,
+      },
+      bo = { filetype = "oil" },
+    }
+
+    _G.vim = mock_vim
+  end
+
+  before_each(function()
+    setup_mocks()
+    integrations = require("claudecode.integrations")
+  end)
+
+  describe("_get_oil_selection", function()
+    it("should get single file under cursor in normal mode", function()
+      local mock_oil = {
+        get_cursor_entry = function()
+          return { type = "file", name = "main.lua" }
+        end,
+        get_current_dir = function(bufnr)
+          return "/Users/test/project/"
+        end,
+      }
+
+      package.loaded["oil"] = mock_oil
+
+      local files, err = integrations._get_oil_selection()
+
+      expect(err).to_be_nil()
+      expect(files).to_be_table()
+      expect(#files).to_be(1)
+      expect(files[1]).to_be("/Users/test/project/main.lua")
+    end)
+
+    it("should get directory under cursor in normal mode", function()
+      local mock_oil = {
+        get_cursor_entry = function()
+          return { type = "directory", name = "src" }
+        end,
+        get_current_dir = function(bufnr)
+          return "/Users/test/project/"
+        end,
+      }
+
+      package.loaded["oil"] = mock_oil
+
+      local files, err = integrations._get_oil_selection()
+
+      expect(err).to_be_nil()
+      expect(files).to_be_table()
+      expect(#files).to_be(1)
+      expect(files[1]).to_be("/Users/test/project/src/")
+    end)
+
+    it("should skip parent directory entries", function()
+      local mock_oil = {
+        get_cursor_entry = function()
+          return { type = "directory", name = ".." }
+        end,
+        get_current_dir = function(bufnr)
+          return "/Users/test/project/"
+        end,
+      }
+
+      package.loaded["oil"] = mock_oil
+
+      local files, err = integrations._get_oil_selection()
+
+      expect(err).to_be("No file found under cursor")
+      expect(files).to_be_table()
+      expect(#files).to_be(0)
+    end)
+
+    it("should handle symbolic links", function()
+      local mock_oil = {
+        get_cursor_entry = function()
+          return { type = "link", name = "linked_file.lua" }
+        end,
+        get_current_dir = function(bufnr)
+          return "/Users/test/project/"
+        end,
+      }
+
+      package.loaded["oil"] = mock_oil
+
+      local files, err = integrations._get_oil_selection()
+
+      expect(err).to_be_nil()
+      expect(files).to_be_table()
+      expect(#files).to_be(1)
+      expect(files[1]).to_be("/Users/test/project/linked_file.lua")
+    end)
+
+    it("should handle visual mode selection", function()
+      -- Mock visual mode
+      mock_vim.fn.mode = function()
+        return "V"
+      end
+      mock_vim.api.nvim_get_mode = function()
+        return { mode = "V" }
+      end
+
+      -- Mock visual_commands module
+      package.loaded["claudecode.visual_commands"] = {
+        get_visual_range = function()
+          return 2, 4 -- Lines 2 to 4
+        end,
+      }
+
+      local line_entries = {
+        [2] = { type = "file", name = "file1.lua" },
+        [3] = { type = "directory", name = "src" },
+        [4] = { type = "file", name = "file2.lua" },
+      }
+
+      local mock_oil = {
+        get_current_dir = function(bufnr)
+          return "/Users/test/project/"
+        end,
+        get_entry_on_line = function(bufnr, line)
+          return line_entries[line]
+        end,
+      }
+
+      package.loaded["oil"] = mock_oil
+
+      local files, err = integrations._get_oil_selection()
+
+      expect(err).to_be_nil()
+      expect(files).to_be_table()
+      expect(#files).to_be(3)
+      expect(files[1]).to_be("/Users/test/project/file1.lua")
+      expect(files[2]).to_be("/Users/test/project/src/")
+      expect(files[3]).to_be("/Users/test/project/file2.lua")
+    end)
+
+    it("should handle errors gracefully", function()
+      local mock_oil = {
+        get_cursor_entry = function()
+          error("Failed to get cursor entry")
+        end,
+      }
+
+      package.loaded["oil"] = mock_oil
+
+      local files, err = integrations._get_oil_selection()
+
+      expect(err).to_be("Failed to get cursor entry")
+      expect(files).to_be_table()
+      expect(#files).to_be(0)
+    end)
+
+    it("should handle missing oil.nvim", function()
+      package.loaded["oil"] = nil
+
+      local files, err = integrations._get_oil_selection()
+
+      expect(err).to_be("oil.nvim not available")
+      expect(files).to_be_table()
+      expect(#files).to_be(0)
+    end)
+  end)
+
+  describe("get_selected_files_from_tree", function()
+    it("should detect oil filetype and delegate to _get_oil_selection", function()
+      mock_vim.bo.filetype = "oil"
+
+      local mock_oil = {
+        get_cursor_entry = function()
+          return { type = "file", name = "test.lua" }
+        end,
+        get_current_dir = function(bufnr)
+          return "/path/"
+        end,
+      }
+
+      package.loaded["oil"] = mock_oil
+
+      local files, err = integrations.get_selected_files_from_tree()
+
+      expect(err).to_be_nil()
+      expect(files).to_be_table()
+      expect(#files).to_be(1)
+      expect(files[1]).to_be("/path/test.lua")
+    end)
+  end)
+end)