diff --git a/layers/+lang/ruby/README.org b/layers/+lang/ruby/README.org
index bc52625ca381..e819ba290a3f 100644
--- a/layers/+lang/ruby/README.org
+++ b/layers/+lang/ruby/README.org
@@ -15,6 +15,7 @@
    - [[#tests][Tests]]
      - [[#rspec-mode][RSpec-mode]]
      - [[#ruby-test-mode][Ruby-test-mode]]
+   - [[#seeing-is-believing][seeing-is-believing]]
    - [[#rake][Rake]]
 
 * Description
@@ -48,6 +49,7 @@ based on your version manager):
 - =pry= and =pry-doc= are required for *jump to definition* and *code documentation* (=robe-mode=)
 - =ruby_parser= is required for *goto-step_definition* in =feature-mode=
 - =rubocop= is required for rubocop integration
+- =seeing_is_believing= helps you evaluate code inline
 
 You can install the gems in the context of your current project by
 adding them to the =Gemfile=, e.g.:
@@ -164,6 +166,13 @@ When =ruby-test-runner= equals =ruby-test=.
 | ~SPC m t b~ | run test file       |
 | ~SPC m t t~ | run test at pointer |
 
+** seeing-is-believing
+
+| Key Binding     | Description                      |
+|-----------------+----------------------------------|
+| ~<SPC> m s b~   | Run seeing is believing          |
+| ~<SPC> m s c~   | Clear seeing is believing output |
+
 ** Rake
 
 | Key binding | Description                     |
diff --git a/layers/+lang/ruby/packages.el b/layers/+lang/ruby/packages.el
index d493d74368fa..299834fb211b 100644
--- a/layers/+lang/ruby/packages.el
+++ b/layers/+lang/ruby/packages.el
@@ -25,6 +25,7 @@
         (ruby-mode :location built-in :toggle (not ruby-enable-enh-ruby-mode))
         ruby-test-mode
         ruby-tools
+        seeing-is-believing
         rvm
         smartparens
         rake
@@ -53,6 +54,20 @@
       (dolist (mode '(ruby-mode enh-ruby-mode))
         (push mode company-dabbrev-code-modes)))))
 
+(defun seeing-is-believing/init-seeing-is-believing ()
+  (use-package seeing-is-believing
+    :defer t
+    :commands (seeing-is-believing seeing-is-believing-run seeing-is-believing-clear)
+    :if (executable-find "seeing_is_believing")
+    :init
+    (progn
+      (dolist (hook '(ruby-mode-hook enh-ruby-mode-hook))
+        (add-hook hook 'seeing-is-believing))
+      (dolist (mode '(ruby-mode enh-ruby-mode))
+        (spacemacs/set-leader-keys-for-major-mode mode
+          "sb" 'seeing-is-believing-run
+          "sc" 'seeing-is-believing-clear)))))
+
 (defun ruby/init-chruby ()
   (use-package chruby
     :if (equal ruby-version-manager 'chruby)