Ignacy Hugo Matuszewski (born September 10, 1891 in Warsaw, died on August 3, 1946 in New York City) was a Polish politician, publicist, diplomat, Minister of Treasury of the Second Polish Republic, colonel, infantry officer and intelligence agent of the Polish Army, member of the International Olympic Committee.

He was a son of Ignacy Matuszewski, Sr., a well-known literary critic. A strong supporter of Józef Piłsudski, he was counted among the "Colonels" and co-founded the Józef Piłsudski Institute of America. He was also the godson of writer, Bolesław Prus.

Ignacy Matuszewski studied philosophy at the Jagiellonian University, architecture in Milan, law in Tartu, and agriculture in Warsaw.

During World War I Matuszewski was one of the executors of Piłsudski's concept in the Russian Empire. From December 1914, he served in the Russian Army, among others as commander of an intelligence troop. After the February Revolution in 1917, he organized the Assembly of Free Poles in Saint Petersburg and participated in the formation of the Polish Corps in Russia. In December 1917 he joined the Polish I Corps in Russia under the command of General Józef Dowbor-Muśnicki.

In the early 1918, Matuszewski received a default death sentence from the Bolsheviks. In response to this threat, he captured Minsk, chasing away the Bolshevik garrison, on February 18, 1918. Two days later, he became the commander of the city. Since the Germans had also sentenced him to death, he decided to move to Kiev. In April 1918, Matuszewski joined the Polish Military Organisation. In May 1918, he participated in the coup directed against General Dowbor-Muśnicki, who wanted to hand control of the Polish I Corps to the Germans at the fortress of Bobrujsk. After the coup failed and the Germans disarmed the Corps, Matuszewski was back in Kiev.

Following the regaining of independence by Poland in November 1918, Matuszewski was transferred to the Second Unit of the General Staff of the Polish Army, of which he became chief at the culmination of the Polish-Bolshevik War. After the Bolshevik defeat, Józef Piłsudski summarized the espionage activity of Matuszewski in the following words: "It was the first war since many centuries waged by Poland during which we [Poland] knew more about the enemy than the enemy knew about us." Matuszewski participated in the talks that resulted in the 1921 Treaty of Riga.

From November 2, 1923 until October 15, 1924, Matuszewski was a listener of the III Training Course at the Wyższa Szkoła Wojenna in Warsaw. After the completion of the course and obtaining of an officer's diploma at the General Staff of the Army, he was appointed military attaché in Rome by the Minister of Military Affairs. On December 1, 1924, he was named elder colonel as of August 15, 1924, and ranked nineteenth in the infantry officers' corps. He was moved to the reserves in 1926.

After the May Coup of 1926, Matuszewski was one of the leading representatives of the right-wing among the followers of Marshal Józef Piłsudski. During 1926-28, he served as a Polish representative in Budapest. During 1929-31, he was director of the Ministry of Treasury and Minister of Treasury in the five following governments (from the cabinet of Kazimierz Świtalski until the second cabinet of Walery Sławek). Between 1932 and 1936, he was the leading publicist of Gazeta Polska (Polish Gazette), whose print run was 35,000 during that period. After Matuszewski's resignation from the newspaper's editing staff, the printing run fell by half. He was also the leading editor of Polityka Narodów, a monthly that analyzed geopolitics, foreign policies of foreign powers, international situation and the place of Poland in the world. In 1937, Matuszewski was awarded the Golden Wawrzyn Akademicki (Academic laurel) by the Polish Academy of Literature for his "services for the good of literature.".

In March 1938, Matuszewski predicted the prompt outbreak of World War II and its fatal consequences for Poland. On the pages of the Słowo Lwowskie (a Vilnus newspaper), the ex-Minister of Treasury launched a campaign for an increase in the Polish war budget and the formation of three armored divisions. After the Germans had captured Prague on March 15, 1939, he wrote an article in Polityka Gospodarcza calling for the doubling the size of the Polish Army. The anxious government elite had Matuszewski's text confiscated, but it appeared in a slightly changed form in Słowo. He was a pessimist, whom Józef Beck did not want to listen. He worried that war would be an unprecedented catastrophe for Poland. The war émigré Władysław Studnicki would later confirm the colonel's critical attitude toward Beck.

Matuszewski thought that Poland could not afford a war with Germany as the Germans had an enormous military advantage. On the eve of the 1939 September Campaign, he said, "we must lose this war miserably within three months." He also anticipated the destruction of the Republic by two aggressors, Nazi Germany and the Soviet Union.

In September 1939, he organized, together with Henryk Floyar-Rajchman, the operation to evacuate 75 tons of gold from the Polish Bank through Romania, Turkey, and Syria to France, where he handed it over to the Polish Government-in-Exile. Removed from service by the government of Władysław Sikorski, he arrived in the United States in September 1941 after the capitulation of France in June 1940, having traveled through Spain, Portugal, and Brazil.

He was opposed to the policies of Władysław Sikorski toward the Soviet Union, for example the Sikorski-Mayski Agreement, which he criticized in his writing. Together with Wacław Jędrzejewicz and Henryk Floyar-Rajchman, Matuszewski co-founded the National Committee of Americans of Polish Extraction (KNAPP) and the Józef Piłsudski Institute of America. He worked to persuade Polish public opinion in the U.S. to oppose the policy of concessions to Joseph Stalin.

He died in New York on August 3, 1946. He was the husband of Halina Konopacka.

"His greatest joy in life," confessed Bohdan Podoski after Matuszewski's death, "was his only daughter, Ewa. He once gave her that what he valued the most, his great-grandfather's and his own Virtuti Militari crosses. The young girl died in the Warsaw Uprising, shot as she was treating wounded soldiers of the Home Army. She was taken by the Germans, whom she did not fear, fulfilling her duty to the end, and was eventually executed for the 'crime' of helping 'lawless individuals.'" Ewa Matuszewska from the sanitary group of the Baszta Company was killed on September 26, 1944, on the Aleja Niepodległości (Independence Avenue) in Warsaw.

Matuszewski received the Silver Cross of the Virtuti Militari and the Estonian Cross of Freedom of the third degree.