This article is about the demographic features of the population of the Czech Republic, including population density, ethnicity, education level, health of the populace, economic status, religious affiliations and other aspects of the population.

With an estimated population of 10,542,080 at 30 June 2011, compared to 9.3 million at the beginning of the twentieth century, the population growth of the Czech Republic was limited and characterized by low fertility rates and loss of population in and around WW I and WW II. Population loss during WW I was approximately 350,000. At the beginning of WW II population the Czech Republic reached its maximum (11.2 million). Due to the expulsion of the German residents after WW II the Czech Republic lost about 3 million inhabitants and in 1947 the population was only 8.8 million. Population growth resumed until 1994 when the population was 10.3 million. From 1994-2005 natural growth was negative and the population decreased to 10.2 million. Since 2006, natural growth has been positive, but the most important factor for the recent population of the Czech Republic has been immigration, approximately 300,000 during the last decade.

The term Spanish people (or Spaniards) has two distinct meanings: Traditionally, it applies to people native to any part of Spain. More recently, it has also come to have a legal meaning, referring to people who hold Spanish citizenship.

Within Spain there are a number of nationalisms and regionalisms, reflecting the country's complex history. The official language of Spain is Spanish (also known as Castilian), a standard language based on the mediaeval dialect of the Castilians of north-central Spain. There are several commonly spoken regional languages. With the exception of Basque, the languages native to Spain are Romance languages.

There are substantial populations outside Spain with ancestors who emigrated from Spain; most notably in Latin America.

The earliest modern humans inhabiting Spain are believed to have been Neolithic peoples who may have arrived in the Iberian Peninsula as early as 35,000­–40,000 years ago. In more recent times the Iberians are believed to have arrived or developed in the region between the 4th millennium BC and the 3rd millennium BC, initially settling along the Mediterranean coast. Celts settled in Spain during the Iron Age. Some of those tribes in North-central Spain, which had cultural contact with the Iberians, are called Celtiberians. In addition, a group known as the Tartessians and later Turdetanians inhabited southwestern Spain and who are believed to have developed a separate civilization of Phoenician influence. The seafaring Phoenicians, Greeks, and Carthaginians successively founded trading colonies along the Mediterranean coast over a period of several centuries. The Second Punic War between the Carthaginians and Romans was fought mainly in what is now Spain and Portugal.