diff --git a/test/ruby/test_fiber.rb b/test/ruby/test_fiber.rb
index ca1b68a73b..3b2faa9802 100644
--- a/test/ruby/test_fiber.rb
+++ b/test/ruby/test_fiber.rb
@@ -311,7 +311,9 @@ class TestFiber < Test::Unit::TestCase
           Fiber.new {
             xpid = fork do
               # enough to trigger GC on old root fiber
-              10000.times do
+              count = 10000
+              count = 1000 if /openbsd/i =~ RUBY_PLATFORM
+              count.times do
                 Fiber.new {}.transfer
                 Fiber.new { Fiber.yield }
               end