It happened several times in the House of Orange-Nassau when they were Prince of Orange:
William the Silent was married 4 times his first and second wives were both called Anna (Anna of Buren and Anna of Saxony)
His grandson William II was married to Mary (the first Princess Royal) their son William III married his cousin Mary later Queen Mary II.
William V married princess Wilhelmina of Prussia their oldest son William VI (later king William I) married her niece another Wilhelmina of Prussia.
I believe that Prussia had two consecutive queens consort named Sophia -- Sophia Charlotte (second wife of King Friedrich I) and Sophia Dorothea (wife of King Friedrich Wilhelm I), who was her niece and daughter-in-law.
Denmark had two consecutive queens consort named Louise -- Princess Louise of Hesse-Cassel (wife of King Christian IX) and Princess Louise of Sweden and Norway (wife of King Frederik VIII), her daughter-in-law.
What are other cases in European royal history, whereby two consecutive queens consort had the same name? I would imagine that with so many queens named Mary, it's plausible this is a repeat name. Of course, queens named Mary typically have had second names to distinguish themselves from one another.
Bavaria had no queen for nearly a quarter of a century, after the death in 1889 of Marie (widow of King Maximilian II and mother of Kings Ludwig II and Otto). As it was, Ludwig III (who was destined to be the last king) assumed the throne in 1913, and his wife was duly proclaimed queen on the occasion. But although she was Marie's *successor* as queen consort, she did not immediately follow her *predecessor*. Also, she was styled as Queen Maria Theresia (not just Maria of Marie). So I'm not sure if this example counts ...
Anyhow, I was just wondering if there have been additional examples.