diff --git a/lib/ex_unit/lib/ex_unit/assertions.ex b/lib/ex_unit/lib/ex_unit/assertions.ex
index 0b7596fca97..87b01150beb 100644
--- a/lib/ex_unit/lib/ex_unit/assertions.ex
+++ b/lib/ex_unit/lib/ex_unit/assertions.ex
@@ -34,7 +34,7 @@ defmodule ExUnit.Assertions do
   """
 
   @doc """
-  Asserts it's argument is true.
+  Asserts its argument is true.
 
   `assert` tries to be smart and provide good
   reporting whenever there is a failure. In particular, if
diff --git a/lib/mix/lib/mix/dep.ex b/lib/mix/lib/mix/dep.ex
index c00f2593cd9..c874c985fd0 100644
--- a/lib/mix/lib/mix/dep.ex
+++ b/lib/mix/lib/mix/dep.ex
@@ -62,7 +62,7 @@ defmodule Mix.Dep do
   end
 
   @doc """
-  Receives a list of  dependency names and returns loaded `Mix.Dep`s.
+  Receives a list of dependency names and returns loaded `Mix.Dep`s.
   Logs a message if the dependency could not be found.
 
   ## Exceptions
diff --git a/lib/mix/lib/mix/remote_converger.ex b/lib/mix/lib/mix/remote_converger.ex
index f3b53dec5e3..e9de940ffa6 100644
--- a/lib/mix/lib/mix/remote_converger.ex
+++ b/lib/mix/lib/mix/remote_converger.ex
@@ -20,7 +20,7 @@ defmodule Mix.RemoteConverger do
   defcallback converge([Mix.Dep.t], map) :: map
 
   @doc """
-  Returns a child dependencies the converger has  for the
+  Returns child dependencies the converger has for the
   dependency. This list should filter the loaded children.
   """
   defcallback deps(Mix.Dep.t, map) :: [atom]
diff --git a/lib/mix/lib/mix/scm.ex b/lib/mix/lib/mix/scm.ex
index 388afa58091..08ccac172a8 100644
--- a/lib/mix/lib/mix/scm.ex
+++ b/lib/mix/lib/mix/scm.ex
@@ -80,11 +80,11 @@ defmodule Mix.SCM do
   @doc """
   This behaviour function checks the status of the lock. In
   particular, it checks if the revision stored in the lock
-  is the same as the repository is currently in. It may return:
+  is the same as the repository it is currently in. It may return:
 
   * `:mismatch` - if the lock doesn't match and we need to
     simply move to the latest lock
-  * `:outdated` - the repository options are out of dated in the
+  * `:outdated` - the repository options are outdated in the
     lock and we need to trigger a full update
   * `:ok` - everything is fine
 
@@ -106,7 +106,7 @@ defmodule Mix.SCM do
   defcallback equal?(opts1 :: opts, opts2 :: opts) :: boolean
 
   @doc """
-  Returns all available SCM. Each SCM is tried in order
+  Returns all available SCMs. Each SCM is tried in order
   until a matching one is found.
   """
   def available do
@@ -123,7 +123,7 @@ defmodule Mix.SCM do
   end
 
   @doc """
-  Aopend the given SCM module to the list of available SCMs.
+  Append the given SCM module to the list of available SCMs.
   """
   def append(mod) when is_atom(mod) do
     available = Enum.reject(available(), &(&1 == mod))