But, reports Bridget Smith of CBS affiliate KENS-TV in San Antonio, money problems may force the museum to close its doors or move to another state.
Even with support from collectors around the world, the museum fails to get the steady admission revenues from tourists that it needs to keep its collections fresh and its doors open to the public.
"We're looking at the possibility of closing because we can't continue to operate in the red and our debtors are getting impatient," said Tom Purdom, a museum administrator. An alternative to closing is a move out of Texas. Sites in New York and Florida, which have larger tourist industries, are being considered, Purdom said.
The museum is home to 300 paintings and drawings by the Bavarian-born nun whose art work, produced during the oppressive Nazi era, showed country children going about their daily lives in scenes of innocence and joy remembered from her youth.
The art was reproduced in the 1920s and 1930s on note cards and in book illustrations, and proceeds from their sales supported her convent's mission efforts for years.
In an unusual partnership, the German porcelain firm W. Goebel Porzellanfabrik obtained permission from the convent in Siessen to turn the paintings into a line of figurines.
From 1935 until her death in 1946 at age 37, Sister Hummel worked with the company to produce the collectibles. World War II restricted production of the figurines. But after the war, they became immensely popular among American GIs who brought them home.
"I thinks it was because she did mostly children, and it was dear to her heart," said Hummel lover Myrtle Weght about the universal appeal of the figurines.
The Texas gallery houses the largest collection of the figurines in the world. It is home to about 1,500 figurines, with price tags ranging from $80 to $22,000.
It has a gift shop that sells the figurines as well as plates and calendars, and the museum occasionally sponsors demonstrations by artisans from the German factory.
But even all this cannot keep the enterprise afloat. Without additional help or more tourist dollars, the museum may be celebrating its last holiday season in Texas.