diff --git a/interfaces/atom.js.flow b/interfaces/atom.js.flow
index 002d270e87..05fb25c2db 100644
--- a/interfaces/atom.js.flow
+++ b/interfaces/atom.js.flow
@@ -81,6 +81,13 @@ declare module 'atom' {
     destroyItem(item: any): boolean;
   }
 
+  declare class Range {
+    intersectsRow(row: number): boolean;
+    start: Point;
+    end: Point;
+    copy(): Range;
+  }
+
   declare class TextBuffer {
     onDidSave(fn: Function): Disposable;
     onDidReload(fn: Function): Disposable;
diff --git a/lib/editor-ops.js b/lib/editor-ops.js
new file mode 100644
index 0000000000..90d4831ec1
--- /dev/null
+++ b/lib/editor-ops.js
@@ -0,0 +1,62 @@
+/* @flow */
+
+import GitStore from './git-store'
+import FileListViewModel from './file-list-view-model'
+import FileDiff from './file-diff'
+import HunkLine from './hunk-line'
+
+import type {Range} from 'atom'
+
+export function stageOrUnstageSelectedLines (gitStore: GitStore, fileListViewModel: FileListViewModel): void {
+  const editor = atom.workspace.getActiveTextEditor()
+  if (editor) {
+    const selectedRanges = editor.getSelectedBufferRanges()
+    const [_projectPath, relativePath] = editor.project.relativizePath(editor.getPath())
+    stageBufferRanges(selectedRanges, relativePath, gitStore, fileListViewModel)
+  }
+}
+
+export async function stageBufferRanges (ranges: Array<Range>, filePath: string, gitStore: GitStore, fileListViewModel: FileListViewModel): Promise<void> {
+  await gitStore.loadFromGit()
+  const fileDiff = fileListViewModel.getDiffForPathName(filePath)
+  const [changedLines, stageOrUnstage] = getChangedLinesAndStagingType(fileDiff, ranges)
+  await gitStore.stageLines(changedLines, stageOrUnstage)
+}
+
+export function getChangedLinesAndStagingType (fileDiff: FileDiff, ranges: Array<Range>): [Array<HunkLine>, boolean] {
+  let lineOffsetSoFar = 0
+
+  ranges = ranges.map(range => {
+    // If a range spans at least one line, and ends on column zero we don't
+    // want to stage the last line (since no text on that line is selected).
+    // So, copy the range and rewind the ending row by 1.
+    if (range.end.column === 0 && range.start.row !== range.end.row) {
+      range = range.copy()
+      range.end.row = range.end.row - 1
+    }
+    return range
+  })
+
+  const anyRangesIntersectLine = (ranges, line) => {
+    // Added/deleted lines mess up the row offset; account for them
+    let row
+    if (line.isAddition()) {
+      row = line.getNewLineNumber() - 1
+      lineOffsetSoFar++
+    } else {
+      row = line.getOldLineNumber()
+      lineOffsetSoFar--
+    }
+    if (line.isDeletion()) row += lineOffsetSoFar
+    return ranges.some(range => range.intersectsRow(row))
+  }
+
+  const linesChangedInRange = fileDiff.getHunks()
+    .map(hunk => hunk.getLines())
+    .reduce((acc, lines) => acc.concat(lines), [])
+    .filter(line => line.isChanged() && anyRangesIntersectLine(ranges, line))
+
+  const linesToStage = linesChangedInRange.filter(line => !line.isStaged())
+
+  return linesToStage.length ? [linesToStage, true] : [linesChangedInRange, false]
+}
diff --git a/lib/git-package.js b/lib/git-package.js
index b7be3808b1..3572df07f3 100644
--- a/lib/git-package.js
+++ b/lib/git-package.js
@@ -7,6 +7,7 @@ import DiffViewModel from './diff-view-model'
 import StatusBarViewModel from './status-bar-view-model'
 import GitService from './git-service'
 import {DiffURI} from './common'
+import {stageOrUnstageSelectedLines} from './editor-ops'
 
 import type {Panel, Pane} from 'atom'
 import type {StatusBar, Tile} from 'status-bar'
@@ -43,6 +44,10 @@ export default class GitPackage {
 
     atom.commands.add('atom-workspace', 'git:refresh-status', () => this.update('reload'))
 
+    atom.commands.add('atom-workspace', 'git:stage-or-unstage-selected-lines', () => {
+      stageOrUnstageSelectedLines(this.getGitStore(), this.getFileListViewModel())
+    })
+
     this.update('reload')
 
     if (state.panelVisible) {
diff --git a/spec/editor-ops-spec.js b/spec/editor-ops-spec.js
new file mode 100644
index 0000000000..7dd559293c
--- /dev/null
+++ b/spec/editor-ops-spec.js
@@ -0,0 +1,23 @@
+/** @babel */
+
+import {it} from './async-spec-helpers'
+
+describe('Editor ops', function () {
+  describe('staging and unstaging lines', () => {
+    describe('when no highlighted lines are staged', () => {
+      it('stages changed lines', () => {
+
+      })
+    })
+    describe('when some highlighted lines are staged and some are unstaged', () => {
+      it('stages all unstaged changed lines', () => {
+
+      })
+    })
+    describe('when all highlighted lines are staged', () => {
+      it('unstages all staged lines', () => {
+
+      })
+    })
+  })
+})