diff --git a/src/main.ts b/src/main.ts
index 480764ba..34900b57 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -2,6 +2,7 @@ import * as Config from '@oclif/config'
 import Help from '@oclif/plugin-help'
 
 import {Command} from '.'
+import {splitArgv} from './util'
 
 export class Main extends Command {
   static run(argv = process.argv.slice(2), options?: Config.LoadOptions) {
@@ -15,7 +16,7 @@ export class Main extends Command {
   }
 
   async run() {
-    let [id, ...argv] = this.argv
+    const {id, argv} = splitArgv(this.argv, this.config.commandIDs)
     this.parse({strict: false, '--': false, ...this.ctor as any})
     if (!this.config.findCommand(id)) {
       let topic = this.config.findTopic(id)
diff --git a/src/util.ts b/src/util.ts
index 45f7b2bf..0431a11b 100644
--- a/src/util.ts
+++ b/src/util.ts
@@ -1,3 +1,36 @@
 export function compact<T>(a: (T | undefined)[]): T[] {
   return a.filter((a): a is T => !!a)
 }
+
+/**
+ * Splits argv to command ID and the rest of the array.
+ *
+ * For space-separated subcommands, the ID is built from multiple items in
+ * the source array. For colon-separated subcommands, the argv item is the ID.
+ */
+export function splitArgv(argv: string[], commandIDs: string[]) {
+  let argvIndex = 0
+  let id = ''
+  let idCandidate = argv[argvIndex]
+
+  while (commandIDs.includes(idCandidate) || !id) {
+    if (commandIDs.includes(idCandidate)) {
+      id = idCandidate
+    }
+    argvIndex++
+    if (argvIndex > argv.length) {
+      break
+    }
+
+    idCandidate += ` ${argv[argvIndex]}`
+  }
+
+  if (id === '') {
+    throw new Error('Command ID not found')
+  }
+
+  return {
+    id,
+    argv: argv.slice(argvIndex),
+  }
+}
diff --git a/test/util.test.ts b/test/util.test.ts
new file mode 100644
index 00000000..879bb875
--- /dev/null
+++ b/test/util.test.ts
@@ -0,0 +1,61 @@
+import {expect} from 'fancy-test'
+
+import {splitArgv} from '../src/util'
+
+describe('splitArgv', () => {
+  it('Colon support (no breaking change)', () => {
+    expectEqual(
+      splitArgv(['user:add', 'Peter'], ['user:add']),
+      {id: 'user:add', argv: ['Peter']}
+    )
+  })
+
+  it('Space-separated when topic itself is in the list', () => {
+    expectEqual(
+      splitArgv(['user', 'add', 'Peter'], ['user', 'user add']),
+      {id: 'user add', argv: ['Peter']}
+    )
+  })
+
+  it('Space-separated when topic is missing from the list', () => {
+    expectEqual(
+      splitArgv(['user', 'add', 'Peter'], ['user add']),
+      {id: 'user add', argv: ['Peter']}
+    )
+  })
+
+  it('Similar but not really - topic level', () => {
+    expect(() => splitArgv(['user', 'add', 'Peter'], ['user2'])).to.throw(Error)
+  })
+
+  it('Similar but not really - nested level', () => {
+    expect(() => splitArgv(['user', 'add', 'Peter'], ['user add2'])).to.throw(Error)
+  })
+
+  it('Multiple nesting levels', () => {
+    expectEqual(
+      splitArgv(['user', 'config', 'frontend', 'add', 'key', 'value'], ['user config frontend add']),
+      {id: 'user config frontend add', argv: ['key', 'value']}
+    )
+  })
+
+  it('Multiple nesting levels, ending in the middle', () => {
+    expectEqual(
+      splitArgv(['user', 'config', 'frontend', 'add', 'key', 'value'], ['user config frontend']),
+      {id: 'user config frontend', argv: ['add', 'key', 'value']}
+    )
+  })
+
+  it('Flags', () => {
+    expectEqual(
+      splitArgv(['user', 'add', '--name', 'Peter'], ['user add']),
+      {id: 'user add', argv: ['--name', 'Peter']}
+    )
+  })
+
+})
+
+// Small strongly-typed helper
+function expectEqual(expected: ReturnType<typeof splitArgv>, actual: ReturnType<typeof splitArgv>) {
+  expect(expected).to.deep.equal(actual)
+}