The Kampar language (Kampar: Bahaso Kampau, Jawi: بهاسو كمڤاو), locally known as Ocu (Kampar: Bahaso Ocu), is a Malayic language spoken mainly by the Kampar people, that resides in Kampar Regency, Riau, Indonesia. The linguistic classification of the Kampar language remains a topic of debate, as it is sometimes regarded as a dialect of either Riau Malay or Minangkabau. The Agency for Language Development and Cultivation under Indonesia's Ministry of Primary and Secondary Education officially categorizes Kampar as a Minangkabau dialect spoken in Riau. Similarly, the Minangkabau community considers the Kampar language to be a variant of Minangkabau due to its resemblance to the Limapuluh Kota dialect. However, this perspective is challenged by the Kampar community, where the majority assert that Kampar is a dialect of Riau Malay, distinct from Minangkabau.

In Kampar, like other regional languages in Indonesia, the Kampar language is primarily used for informal communication, with its formal usage mostly limited to traditional ceremonies and customary events. It is also influenced by other languages, particularly Indonesian, the national language, which is predominantly used in formal settings such as government institutions and schools. In addition, the influence of standard Minangkabau complicates the distinction between Kampar and the Minangkabau variety spoken in West Sumatra. For example, ompek in Kampar and ampek in Minangkabau both mean ‘four.’ Similarly, words such as inyo ‘he/she’, apo ‘what’, and tigo ‘three are shared by both languages with identical meanings. Most people in Kampar are bilingual in both Kampar and Indonesian, frequently engaging in code-switching and code-mixing between the two languages. The Kampar language is increasingly threatened by the growing use of Indonesian, leading to the gradual replacement of traditional Kampar vocabulary with Indonesian equivalents.

The classification of the Kampar language remains disputed; however, it is generally recognized as a Malayic language. Speakers of Malayic languages are spread from Brunei, Indonesia, Malaysia, Singapore, Southern Thailand, to the southernmost part of the Philippines. Malay is a member of the Austronesian family of languages, which includes languages from Taiwan, Southeast Asia, and the Pacific Ocean, with a smaller number in continental Asia. Malagasy, a geographic outlier spoken in Madagascar in the Indian Ocean, is also a member of this language family. Although these languages are not necessarily mutually intelligible to any extent, their similarities are often quite apparent. In more conservative languages like Malay, many roots have come with relatively little change from their common ancestor, Proto-Austronesian. There are many cognates found in the languages' words for kinship, health, body parts and common animals. Numbers, especially, show remarkable similarities.

The linguistic classification of Kampar remains a subject of debate. At times, it is considered a dialect of either Riau Malay or Minangkabau. Kampar is a variety within the Malayic language family; however, it has yet to receive a widely accepted language code or internal classification within the Malayic group. The geographical distribution of Kampar, situated between the Minangkabau-speaking region to the west and the Riau Malay-speaking region to the east, has led to mutual linguistic influence between these languages, forming part of a dialect continuum in central Sumatra.

For its speakers, Kampar is referred to as Bahasa Ocu and is considered a variety of Riau Malay, distinct from Minangkabau. In various publications, it is alternatively labeled as Melayu Kampar 'Kampar Malay', Melayu dialek Kampar 'Kampar Malay dialect', or Melayu Riau dialek Kampar 'Kampar Riau Malay dialect'. However, other sources, such as the 1982 book Struktur Bahasa Minangkabau di Kabupaten Kampar published by the Indonesian Ministry of Education and Culture, provide a detailed grammatical description of Minangkabau as spoken in Kampar Regency, suggesting a strong linguistic connection to Minangkabau. Additionally, the 2017 book Bahasa dan Peta Bahasa di Indonesia, also published by the Ministry of Education and Culture, further supports the presence of Minangkabau in Kampar Regency, leading some publications to classify Kampar as Minang Kampar 'Kampar Minangkabau' or Minang dialek Kampar 'Kampar Minangkabau dialect'. Similarly, Masni et al. (2021) found in their study of the Kuntu isolex in Kampar Regency that its phonemic diversity aligns with Minangkabau dialects, despite its administrative location in Riau.

Hamidy (2002) identified six dialects of Riau Malay, distinguished primarily by intonation and lexical differences:

In 2009, a language mapping team from the Riau Provincial Language Center classified Kampar (divided into Kampar and East Kampar dialects) as part of Melayu Darat ‘Inland Malay’, alongside the Kuantan and Rokan dialects.

Similarities between Kampar and Minangkabau, particularly with the Limapuluh Kota dialect, have led some scholars to classify Kampar as a dialect of Minangkabau. Said et al. (1986) stated that the language spoken in western Kampar Regency (which corresponds to the current Kampar Regency after separation of other regencies) is Minangkabau. The Indonesian Agency for Language Development and Cultivation also classifies the Kampar dialect as one of the Minangkabau dialects spoken in Riau, alongside Rokan, Basilam, Indragiri, and Kuantan dialects. The lexical difference between Kampar and other Minangkabau dialects ranges from 51% to 69%. Based on the classification theories of Guiter and Lauder, this percentage indicates that Kampar and Minangkabau are dialectally distinct but closely related languages.